TWI735773B - Bicycle sprocket and bicycle sprocket assembly - Google Patents

Bicycle sprocket and bicycle sprocket assembly Download PDF

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Publication number
TWI735773B
TWI735773B TW107111441A TW107111441A TWI735773B TW I735773 B TWI735773 B TW I735773B TW 107111441 A TW107111441 A TW 107111441A TW 107111441 A TW107111441 A TW 107111441A TW I735773 B TWI735773 B TW I735773B
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TW
Taiwan
Prior art keywords
bicycle sprocket
nickel
layer
teeth
tooth
Prior art date
Application number
TW107111441A
Other languages
Chinese (zh)
Other versions
TW201837346A (en
Inventor
谷口誠典
山內弥
岩井亨
吉田十義
横澤太
Original Assignee
日商島野股份有限公司
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Publication of TW201837346A publication Critical patent/TW201837346A/en
Application granted granted Critical
Publication of TWI735773B publication Critical patent/TWI735773B/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/10—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like
    • B62M9/12—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like the chain, belt, or the like being laterally shiftable, e.g. using a rear derailleur
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/10—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/31—Coating with metals
    • C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/30—Chain-wheels

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Thermal Sciences (AREA)
  • Electromagnetism (AREA)
  • Physics & Mathematics (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Gears, Cams (AREA)
  • Chemically Coating (AREA)

Abstract

[課題] 要提供一種可抑制鏈條脫離的鏈輪。 　　[解決手段] 自行車用鏈輪具備有：具有旋轉中心軸心的鏈輪主體(12)、與複數的齒部(14)；上述複數的齒部(14)包含：在旋轉中心軸心方向具有第1寬度的第1齒部(24)、及在旋轉中心軸心方向具有較第1寬度更小的第2寬度的第2齒部(26)。複數的齒部(14)包含：基體(40)、以及將基體(40)的至少局部覆蓋且包含磷及硼的至少其中一方的鍍鎳層(42)。[Question] To provide a sprocket that can inhibit chain detachment. [Solution] The bicycle sprocket is provided with: a sprocket body (12) with a rotation center axis, and a plurality of teeth (14); the plurality of teeth (14) includes: a sprocket having a rotation center axis direction The first tooth portion (24) with the first width and the second tooth portion (26) with the second width smaller than the first width in the rotation center axis direction. The plural teeth (14) include a base (40) and a nickel plating layer (42) that covers at least a part of the base (40) and contains at least one of phosphorus and boron.

Description

自行車用鏈輪及自行車用鏈輪組件Bicycle sprocket and bicycle sprocket assembly

[0001] 本發明關於自行車用鏈輪、及具備該自行車用鏈輪的自行車用鏈輪組件。[0001] The present invention relates to a bicycle sprocket and a bicycle sprocket assembly including the bicycle sprocket.

[0002] 作為自行車用鏈輪已知有專利文獻1記載的技術。 　　專利文獻1記載的自行車用鏈輪包含：鏈輪主體、複數的齒部。複數的齒部包含：在旋轉中心軸心方向具有第1寬度的第1齒部、與在旋轉中心軸心方向具有較第1寬度更小的第2寬度的第2齒部。 [先前技術文獻] [專利文獻] 　　[0003] 　　[專利文獻1] 美國專利申請公開第2014/0338494號說明書[0002] The technology described in Patent Document 1 is known as a bicycle sprocket.　　 The bicycle sprocket described in Patent Document 1 includes a sprocket body and a plurality of teeth. The plural tooth portions include a first tooth portion having a first width in the rotation center axis direction and a second tooth portion having a second width smaller than the first width in the rotation center axis direction. [Prior Art Document] [Patent Document] 　　[0003] 　　[Patent Document 1] US Patent Application Publication No. 2014/0338494 Specification

[發明所欲解決之問題] 　　[0004] 自行車用鏈輪為了輕量化而是以鋁或鋁合金所構成。在鋁製的鏈輪，容易因與鏈條摩擦而讓齒部磨損。齒部的磨損變多的話，則可能會提高鏈條的脫落頻率。在包含變速區域的自行車用鏈輪，如果設置在變速區域之外的齒部(驅動齒)產生磨損的話，則當變速動作時在變速區域之外容易產生鏈條的脫落，容易因變速失敗導致鏈條脫落。 [解決問題之技術手段] 　　[0005] (1)本發明的第1型態的自行車用鏈輪，具備有：具有旋轉中心軸心的鏈輪主體、與複數的齒部；上述複數的齒部包含：在上述旋轉中心軸心方向具有第1寬度的第1齒部、及在上述旋轉中心軸心方向具有較上述第1寬度更小的第2寬度的第2齒部；上述複數的齒部包含：基體、以及將上述基體的至少局部覆蓋，且包含磷及硼的至少其中一方的鍍鎳層。 　　[0006] 藉由該構造則能提供一種鏈輪，讓其齒部的耐磨損性提升，讓驅動時的鏈條的保持力提升，可長時間抑制鏈條脫落。 　　[0007] (2)本發明的第2型態的自行車用鏈輪，具備有：具有旋轉中心軸心的鏈輪主體、與複數的齒部；上述複數的齒部包含：在上述旋轉中心軸心方向具有第1寬度的第1齒部、及在上述旋轉中心軸心方向具有較上述第1寬度更小的第2寬度的第2齒部；上述複數的齒部包含：基體、以及設置成將上述基體的至少局部覆蓋，且具有硬質粒子的鍍鎳層。 　　[0008] 藉由該構造則能提供一種鏈輪，讓其齒部的耐磨損性提升，讓驅動時的鏈條的保持力提升，可長時間抑制鏈條脫落。 　　[0009] (3)本發明的第3型態的自行車用鏈輪，具備有：具有旋轉中心軸心的鏈輪主體、複數的齒部、至少一個變速區域；上述複數的齒部包含：基體、以及設置成將上述基體的至少局部覆蓋，且具有硬質粒子的鍍鎳層。 　　[0010] 藉由該構造，讓齒部的耐磨損性提升，減少驅動齒的磨損，藉此可抑制在變速區域之外的驅動齒產生無預期的變速。 　　[0011] (4)在依據上述第3型態的第4型態的自行車用鏈輪，上述複數的齒部具有：配置於上述變速區域的變速齒、及配置在與上述變速區域不同的區域的驅動齒；上述鍍鎳層至少形成於上述驅動齒。 　　[0012] 藉由該構造，讓齒部的耐磨損性提升，減少驅動齒的磨損，藉此可抑制在變速區域之外的驅動齒產生無預期的變速。 　　[0013] (5)在依據上述第1或2型態的第5型態的自行車用鏈輪，上述複數的齒部，包含面向上述旋轉中心軸心方向的側面，上述鍍鎳層形成於上述第1齒部的側面。 　　[0014] 藉由該構造，可減少第1齒部(厚齒)的旋轉中心軸心方向的磨損，能長時間維持鏈條的保持力。 　　[0015] (6)在依據上述第1、2、及5型態的第6型態的自行車用鏈輪，上述複數的齒部，包含面向上述旋轉中心軸心方向的側面，上述鍍鎳層形成於上述第2齒部的側面。 　　[0016] 藉由該構造，可減少第2齒部(薄齒)的旋轉中心軸心方向的磨損，進一步能長時間維持鏈條的保持力。 　　[0017] (7)在依據上述第2、3及4型態的第7型態的自行車用鏈輪，上述硬質粒子，包含氧化鋁及二氧化鋯的至少其中一方。 　　[0018] 藉由該構造，則能形成硬質粒子的共晶率較高的鍍鎳層。 　　[0019] (8)在依據上述第2、3、4及7型態的第8型態的自行車用鏈輪，上述硬質粒子的平均粒徑為0.8μm以上。 　　[0020] 藉由該構造，藉由使平均粒徑成為0.8μm以上，能大幅降低磨損量。 　　[0021] (9)在依據上述第2、3、4、7及8型態的第9型態的自行車用鏈輪，上述硬質粒子，設置成相對於與旋轉中心軸心方向平行的上述鍍鎳層的剖面，面積比為10%以上30%以下。 　　[0022] 藉由該構造，藉由使面積比成為10~30%則能大幅降低磨損量。 　　[0023] (10)在依據上述第1型態至第9型態的任一型態的第10型態的自行車用鏈輪，上述基體包含：包含第1材料的第1層部、及包含比重與上述第1材料不同的第2材料的第2層部。 　　[0024] 藉由該構造，能提供既確保強度又輕量化的鏈輪。 　　[0025] (11)在依據上述第10型態的第11型態的自行車用鏈輪，上述第2材料，其比重小於上述第1材料，上述第1層部與第2層部，積疊於上述旋轉中心軸心方向。 　　[0026] 藉由該構造，相較於包含第1材料的情況更能將複數的齒部輕量化。 　　[0027] (12)在依據上述第10或11型態的第12型態的自行車用鏈輪，上述第1材料包含鐵，上述第2材料包含鋁。 　　[0028] 藉由該構造，與只含有鐵的情況相比，可以將自行車用鏈輪輕量化，與只含有鋁的情況相比，能使複數的齒部更高強度化。 　　[0029] (13)在依據上述第10型態至第12型態的任一型態的第13型態的自行車用鏈輪，上述鍍鎳層形成於上述第2層部的外表面。 　　[0030] 藉由該構造，可提升第2層部的外表面的耐磨損性。 　　[0031] (14)在依據上述第10型態至第13型態的任一型態的第14型態的自行車用鏈輪，上述基體包含第3層部，第3層部包含比重較第1材料更小的第3材料；上述第1層部，在上述旋轉中心軸心方向積疊於上述第2層部、與上述第3層部之間。 　　[0032] 藉由該構造，由於重心在旋轉中心軸心方向的中間部分，所以能使自行車用鏈輪的旋轉更穩定。 　　[0033] (15)在依據上述第1型態至第14型態的任一型態的第15型態的自行車用鏈輪，上述鍍鎳層其維氏硬度(Vickers hardness)為500Hv以上。 　　[0034] 藉由該構造，與鍍鎳層的維氏硬度(Vickers hardness)小於500Hv的情況相比，可以更抑制鍍鎳層的磨損。 　　[0035] (16)在依據上述第1型態至第15型態的任一型態的第16型態的自行車用鏈輪，上述基體包含鋁。 　　藉由該構造，與基體是比重較鋁更高的金屬或合金形成的情況相比，能使複數的齒部更輕量化。 　　[0036] (17)在依據上述第1型態至第16型態的任一型態的第17型態的自行車用鏈輪，上述複數的齒部，包含在其與鏈條之間傳遞驅動力的驅動面，上述鍍鎳層形成於上述驅動面。 　　[0037] 藉由該構造，能更提升複數的齒部的驅動面的耐磨損性。 　　[0038] (18)在依據上述第1型態至第17型態的任一型態的第18型態的自行車用鏈輪，上述鍍鎳層至少包含磷，上述鍍鎳層中的磷含有量為0.1質量%以上且10.0質量%以下。 　　[0039] 藉由該構造，與鍍鎳層只包含鎳的情況相比，可提高鍍鎳層的維氏硬度(Vickers hardness)。 　　[0040] (19)在依據上述第18型態的第19型態的自行車用鏈輪，上述鍍鎳層中的磷含有量為1.0質量%以上且5.0質量%以下。 　　[0041] 藉由該構造，與鍍鎳層中的磷含有量小於1.0質量%的情況相比，可提高鍍鎳層的維氏硬度(Vickers hardness)。與鍍鎳層中的磷含有量大於5.0質量%的情況相比，可提高鍍鎳層的維氏硬度(Vickers hardness)。 　　[0042] (20)在依據上述第1型態至第19型態的任一型態的第20型態的自行車用鏈輪，上述鍍鎳層至少包含硼，上述鍍鎳層中的硼含有量為0.1質量%以上且10.0質量%以下。 　　[0043] 藉由該構造，與鍍鎳層只包含鎳的情況相比，可提高鍍鎳層的維氏硬度(Vickers hardness)。 　　[0044] (21)在依據上述第20型態的第21型態的自行車用鏈輪，上述鍍鎳層中的硼含有量為0.1質量%以上且2.0質量%以下。 　　[0045] 藉由該構造，與鍍鎳層中的硼含有量小於0.1質量%的情況相比，可提高鍍鎳層的維氏硬度(Vickers hardness)。與鍍鎳層中的硼含有量大於2.0質量%的情況相比，可提高鍍鎳層的維氏硬度(Vickers hardness)。 　　[0046] (22)在依據上述第1型態至第21型態的任一型態的第22型態的自行車用鏈輪，上述鍍鎳層包含無電解鍍鎳。 　　[0047] 藉由該構造，讓鍍鎳層更緻密，能提升鍍鎳層的耐磨損性。 　　[0048] (23)在依據上述第1型態至第22型態的任一型態的第23型態的自行車用鏈輪，上述鍍鎳層的厚度為1.0μm以上且100μm以下。 　　藉由該構造，與鍍鎳層的厚度小於1.0μm的情況相比，可以更抑制因鍍鎳層磨損讓基體露出。而且與鍍鎳層的厚度大於100μm的情況相比，可更縮短鍍鎳層的形成時間。 　　[0049] (24)在依據上述第23型態的第24型態的自行車用鏈輪，上述鍍鎳層的厚度為5.0μm以上且40.0μm以下。 　　藉由該構造，與鍍鎳層的厚度小於5.0μm的情況相比，可以更抑制因鍍鎳層磨損讓基體露出。而且與鍍鎳層的厚度大於40.0μm的情況相比，可更縮短鍍鎳層的形成時間。 　　[0050] (25)在依據上述第1型態至第24型態的任一型態的第25型態的自行車用鏈輪，上述鏈輪主體包含：含有鋁的基體、及將上述基體的至少局部覆蓋的陽極氧化鋁覆膜。 　　[0051] 藉由該構造，與基體只包含鋁的情況相比，更能將自行車用鏈輪輕量化。陽極氧化鋁覆膜可染色為不同於鋁的其他顏色，所以能使外觀不同於未包含陽極氧化鋁覆膜的自行車用鏈輪。 　　[0052] (26)在依據上述第1型態至第25型態的任一型態的第26型態的自行車用鏈輪，上述自行車用鏈輪，是單片式的前鏈環。 　　[0053] 藉由該構造，能更提升前鏈環的齒部的耐磨損性。 　　[0054] (27)本發明的第27型態的自行車用鏈輪組件，包含有：包含上述第1至26型態中任一型態的自行車用鏈輪的第1鏈環、及包含較上述自行車用鏈輪更小直徑的自行車用鏈輪的第2鏈環。 　　[0055] 藉由該構造，能更提升第1鏈環的齒部的耐磨損性。 　　[0056] (28)在依據上述第27型態的第28型態的自行車用鏈輪組件，上述第2鏈環具備有複數的齒部，上述複數的齒部包含：在上述旋轉中心軸心方向具有第3寬度的第3齒部、與在上述旋轉中心軸心方向具有較上述第3寬度更小的第4寬度的第4齒部。 　　[0057] 藉由該構造，則可抑制鏈條從第2鏈環脫落。 　　[0058] (29)在依據上述第28型態的第29型態的自行車用鏈輪組件，上述第3齒部及上述第4齒部包含：含有鋁的基體、及將上述基體的至少局部覆蓋的陽極氧化鋁覆膜。 　　[0059] 藉由該構造，與基體只包含鋁的情況相比，更能將第2鏈環輕量化。陽極氧化鋁覆膜可染色為不同於鋁的其他顏色，所以能使外觀不同於未包含陽極氧化鋁覆膜的第2鏈環。 　　[0060] (30)在依據上述第28型態或上述第29型態的第30型態的自行車用鏈輪組件，上述第3齒部及上述第4齒部包含：含有鋁的基體、及將上述基體的至少局部覆蓋且包含磷及硼的至少其中一方的無電解鍍鎳。 　　[0061] 藉由該構造，能更提升第2鏈環的第3齒部及第4齒部的耐磨損性。 [發明效果] 　　[0062] 讓上述自行車用鏈輪及自行車用鏈輪組件有高耐磨損性。[Problem to be solved by the invention] 　　[0004] Bicycle sprocket is made of aluminum or aluminum alloy in order to reduce the weight. In aluminum sprocket, it is easy to wear the teeth due to friction with the chain. If the wear of the teeth increases, the frequency of the chain falling off may increase. In bicycle sprockets that include the shifting area, if the teeth (drive teeth) provided outside the shifting area are worn, the chain will easily fall off outside the shifting area during the shifting operation, and the chain will easily be caused by the failure of shifting. Fall off. [Technical Means for Solving the Problem] 　　[0005] (1) The bicycle sprocket according to the first aspect of the present invention includes: a sprocket body having a rotation center axis, and plural teeth; the plural teeth It includes: a first tooth portion having a first width in the direction of the rotation center axis, and a second tooth portion having a second width smaller than the first width in the direction of the rotation center axis; the plurality of teeth It includes a substrate and a nickel plating layer covering at least a part of the substrate and containing at least one of phosphorus and boron.　　[0006] With this structure, a sprocket can be provided, which improves the wear resistance of its teeth, improves the holding force of the chain during driving, and can prevent the chain from falling off for a long time. [0007] (2) A bicycle sprocket according to a second aspect of the present invention includes: a sprocket body having a rotation center axis, and a plurality of teeth; the plurality of teeth include: the rotation center axis A first tooth portion having a first width in the direction of the center of rotation, and a second tooth portion having a second width smaller than the first width in the direction of the rotation center axis; At least part of the substrate is covered with a nickel-plated layer of hard particles.　　[0008] With this structure, a sprocket can be provided, which improves the wear resistance of its teeth, improves the holding force of the chain during driving, and can prevent the chain from falling off for a long time. [0009] (3) A bicycle sprocket according to a third aspect of the present invention includes: a sprocket body having a rotation center axis, a plurality of teeth, and at least one speed change region; the plurality of teeth includes: a base And a nickel-plated layer arranged to cover at least a part of the above-mentioned substrate and having hard particles.　　[0010] With this structure, the wear resistance of the teeth is improved, and the wear of the drive teeth is reduced, thereby preventing unexpected shifting of the drive teeth outside the shifting area. [0011] (4) In the bicycle sprocket of the fourth form according to the third form, the plurality of teeth have: gears arranged in the gear shifting region, and gears arranged in a region different from the gear shifting region The drive teeth; the nickel-plated layer is formed at least on the drive teeth.　　[0012] With this structure, the wear resistance of the teeth is improved, and the wear of the drive teeth is reduced, thereby suppressing unexpected shifting of the drive teeth outside the shifting area. [0013] (5) In the bicycle sprocket according to the fifth form according to the first or second form, the plurality of teeth includes a side surface facing the rotation center axis direction, and the nickel plating layer is formed on the The side of the first tooth.　　[0014] With this structure, it is possible to reduce wear in the axial direction of the rotation center of the first tooth portion (thick tooth), and to maintain the holding force of the chain for a long time. [0015] (6) In a bicycle sprocket according to the sixth form of the first, second, and fifth forms, the plurality of teeth includes a side surface facing the direction of the rotation center axis, and the nickel plating layer It is formed on the side surface of the second tooth portion.　　[0016] With this structure, it is possible to reduce the wear in the axis direction of the rotation center of the second tooth portion (thin tooth), and to further maintain the holding force of the chain for a long time.　　[0017] (7) In the bicycle sprocket of the seventh form according to the second, third, and fourth forms, the hard particles include at least one of alumina and zirconium dioxide.　　[0018] With this structure, a nickel-plated layer with a high eutectic rate of hard particles can be formed.　　[0019] (8) In the bicycle sprocket of the eighth form according to the above-mentioned forms 2, 3, 4, and 7, the average particle diameter of the hard particles is 0.8 μm or more.　　[0020] With this structure, by making the average particle size 0.8 μm or more, the amount of wear can be greatly reduced. [0021] (9) In the bicycle sprocket according to the ninth form of the second, third, fourth, seventh, and eighth form, the hard particles are disposed relative to the plated sprocket parallel to the axis of the rotation center. The cross-section of the nickel layer has an area ratio of 10% or more and 30% or less.　　[0022] With this structure, the amount of wear can be greatly reduced by making the area ratio 10 to 30%. [0023] (10) In the bicycle sprocket of the tenth form according to any one of the first to ninth forms, the base includes: a first layer including a first material, and A second layer portion of a second material having a specific gravity different from the above-mentioned first material.　　[0024] With this structure, it is possible to provide a sprocket that is both strong and lightweight. [0025] (11) In the bicycle sprocket of the eleventh form according to the tenth form, the second material has a smaller specific gravity than the first material, and the first layer portion and the second layer portion are stacked In the direction of the above-mentioned rotation center axis.　　[0026] With this structure, the weight of the plural teeth can be reduced more than when the first material is included.　　[0027] (12) In the bicycle sprocket of the twelfth type according to the tenth or eleventh type, the first material includes iron, and the second material includes aluminum.　　[0028] With this structure, the weight of the bicycle sprocket can be reduced compared to the case where only iron is contained, and the multiple teeth can be made stronger than the case where only aluminum is contained.　　[0029] (13) In a bicycle sprocket of a thirteenth form according to any of the tenth form to the twelfth form, the nickel-plated layer is formed on the outer surface of the second layer part.　　[0030] With this structure, the abrasion resistance of the outer surface of the second layer can be improved. [0031] (14) In the bicycle sprocket of the fourteenth type according to any one of the tenth type to the thirteenth type, the base body includes a third layer portion, and the third layer portion includes a 1 is a third material with a smaller material; the first layer portion is stacked between the second layer portion and the third layer portion in the direction of the rotation center axis.　　[0032] With this structure, since the center of gravity is in the middle of the rotation center axis direction, the rotation of the bicycle sprocket can be made more stable.　　[0033] (15) In the bicycle sprocket of the 15th type according to any of the above-mentioned 1st type to the 14th type, the above-mentioned nickel-plated layer has a Vickers hardness of 500 Hv or more.　　[0034] With this structure, compared with the case where the Vickers hardness of the nickel-plated layer is less than 500Hv, the wear of the nickel-plated layer can be suppressed more.　　[0035] (16) In the bicycle sprocket of the sixteenth form according to any one of the above-mentioned first form to the fifteenth form, the base body includes aluminum.　　 With this structure, the weight of the plural teeth can be reduced compared to the case where the base is formed of a metal or alloy with a higher specific gravity than aluminum. [0036] (17) In the bicycle sprocket of the 17th form according to any of the above-mentioned 1st form to the 16th form, the plurality of teeth are included to transmit driving force between the chain and the chain. On the driving surface, the nickel-plated layer is formed on the driving surface.　　[0037] With this structure, it is possible to further improve the wear resistance of the driving surface of the plural teeth. [0038] (18) In the bicycle sprocket of the 18th form according to any one of the above-mentioned first to 17th forms, the nickel-plated layer contains at least phosphorus, and the phosphorus in the nickel-plated layer contains The amount is 0.1% by mass or more and 10.0% by mass or less.　　[0039] With this structure, the Vickers hardness of the nickel-plated layer can be increased compared to the case where the nickel-plated layer only contains nickel.　　[0040] (19) In the bicycle sprocket of the 19th mode according to the above-mentioned 18th mode, the phosphorus content in the nickel plating layer is 1.0% by mass or more and 5.0% by mass or less.　　[0041] With this structure, the Vickers hardness of the nickel-plated layer can be increased compared to the case where the phosphorus content in the nickel-plated layer is less than 1.0% by mass. Compared with the case where the phosphorus content in the nickel-plated layer is greater than 5.0% by mass, the Vickers hardness of the nickel-plated layer can be increased. [0042] (20) In the bicycle sprocket of the twentieth type according to any one of the above-mentioned first to nineteenth types, the nickel-plated layer contains at least boron, and the boron in the nickel-plated layer contains The amount is 0.1% by mass or more and 10.0% by mass or less.　　[0043] With this structure, the Vickers hardness of the nickel-plated layer can be increased compared to the case where the nickel-plated layer contains only nickel.　　[0044] (21) In the bicycle sprocket of the 21st form according to the 20th form, the content of boron in the nickel plating layer is 0.1% by mass or more and 2.0% by mass or less.　　[0045] With this structure, the Vickers hardness of the nickel-plated layer can be increased compared to the case where the boron content in the nickel-plated layer is less than 0.1% by mass. Compared with the case where the boron content in the nickel-plated layer is greater than 2.0% by mass, the Vickers hardness of the nickel-plated layer can be increased.　　[0046] (22) In the bicycle sprocket of the 22nd form according to any one of the above-mentioned 1st to 21st forms, the nickel plating layer includes electroless nickel plating.　　[0047] With this structure, the nickel-plated layer is denser and the wear resistance of the nickel-plated layer can be improved.　　[0048] (23) In the bicycle sprocket of the 23rd type according to any of the above-mentioned first to 22nd types, the thickness of the nickel plating layer is 1.0 μm or more and 100 μm or less.　　 With this structure, compared with the case where the thickness of the nickel plating layer is less than 1.0 μm, it is possible to suppress the exposure of the substrate due to the wear of the nickel plating layer. Moreover, compared with the case where the thickness of the nickel-plated layer is greater than 100 μm, the formation time of the nickel-plated layer can be further shortened.　　[0049] (24) In the bicycle sprocket of the 24th form according to the above-mentioned 23rd form, the thickness of the nickel-plated layer is 5.0 μm or more and 40.0 μm or less.　　 With this structure, compared with the case where the thickness of the nickel plating layer is less than 5.0 μm, it is possible to suppress the exposure of the substrate due to the wear of the nickel plating layer. Moreover, compared with the case where the thickness of the nickel-plated layer is greater than 40.0 μm, the formation time of the nickel-plated layer can be further shortened. [0050] (25) In the bicycle sprocket of the 25th form according to any one of the above-mentioned first form to the 24th form, the sprocket body includes: a base containing aluminum, and a base that combines the base At least partially covered anodized aluminum film.　　[0051] With this structure, it is possible to reduce the weight of the bicycle sprocket compared to the case where the base body only contains aluminum. The anodized aluminum film can be dyed in colors other than aluminum, so the appearance can be different from bicycle sprockets that do not contain an anodized aluminum film.　　[0052] (26) In the 26th type bicycle sprocket according to any one of the above-mentioned 1st type to the 25th type, the above-mentioned bicycle sprocket is a single-piece front chain link.　　[0053] With this structure, the wear resistance of the teeth of the front link can be further improved. [0054] (27) The 27th aspect of the bicycle sprocket assembly of the present invention includes: a first chain ring that includes any of the above-mentioned first to 26th aspects of the bicycle sprocket, and a The second chain link of the bicycle sprocket with a smaller diameter of the bicycle sprocket.　　[0055] With this structure, the wear resistance of the teeth of the first link can be further improved. [0056] (28) In the bicycle sprocket assembly according to the twenty-seventh aspect and the twenty-eighth aspect, the second chain ring is provided with a plurality of teeth, and the plurality of teeth includes: on the rotation center axis A third tooth portion having a third width in the direction, and a fourth tooth portion having a fourth width smaller than the third width in the direction of the rotation center axis.　　[0057] With this structure, the chain can be prevented from falling off the second link. [0058] (29) In the bicycle sprocket assembly of the 29th form according to the 28th form, the third tooth portion and the fourth tooth portion include: a base body containing aluminum, and at least a part of the base body Covered with anodized aluminum film.　　[0059] With this structure, the weight of the second link can be reduced more than when the base contains only aluminum. The anodized aluminum film can be dyed in other colors different from aluminum, so the appearance can be different from the second link that does not include the anodized aluminum film. [0060] (30) In the bicycle sprocket assembly of the 30th form according to the 28th form or the 29th form, the third tooth portion and the fourth tooth portion include: a base containing aluminum, and Electroless nickel plating that covers at least part of the substrate and contains at least one of phosphorus and boron.　　[0061] With this structure, the wear resistance of the third tooth portion and the fourth tooth portion of the second link can be further improved. [Effects of the Invention] 　　[0062] The above-mentioned bicycle sprocket and bicycle sprocket assembly have high wear resistance.

[0064] ＜第1實施方式＞ 　　參考第1圖，針對自行車變速時的鏈條的動作來說明。第1圖是從上方觀察自行車2的視圖，主要是自行車的傳動系統的示意圖。 　　自行車2至少具備有：自行車用鏈輪的一種型態也就是前鏈輪4、自行車用鏈輪的一種型態也就是後鏈輪6、繞掛於前鏈輪4及後鏈輪6的鏈條8、撥鏈器10。 　　[0065] 在各實施方式的說明，將繞掛有鏈條8的後鏈輪6從預定的後鏈輪6變更成較該預定的後鏈輪6更小直徑的後鏈輪6的情形稱為「第1換檔」。將繞掛有鏈條8的後鏈輪6從預定的後鏈輪6變更成較該預定的後鏈輪6更大直徑的後鏈輪6的情形稱為「第2換檔」。 　　[0066] 當第1換檔及第2換檔時，藉由撥鏈器10的動作，讓鏈條8的後方部分朝後鏈輪6的旋轉中心軸心方向Dr移動。具體來說，在本實施方式，當第1換檔時，鏈條8的後方部朝旋轉中心軸心方向Dr的右方(自行車相對於中心面Pb的外側方向)(小直徑的後鏈輪6)移動。第2換檔時，鏈條8的後方部朝旋轉中心軸心方向Dr的左方(大直徑的後鏈輪6側)移動。 　　因此，鏈條8的傾斜角度AG，會因為鏈條8是繞掛於任一後鏈輪6而有所不同。所謂鏈條8的傾斜角度AG，是表示包含前鏈輪4的旋轉軌道的平面P1、與鏈條8繞掛於預定的後鏈輪6時包含鏈條8的軌道的平面P2所構成的角度。平面P1及平面P2，是在自行車豎立的狀態相對於水平面正交的面。 　　[0067] 參考第2圖及第3圖，針對本實施方式的前鏈輪4來說明。 　　前鏈輪4，在本實施方式，是單片式的前鏈環。 　　前鏈輪4，包含有：具有旋轉中心軸心C1的鏈輪主體12、複數的齒部14。 　　鏈輪主體12，具有：具有前鏈輪4的旋轉中心軸心C1的第1環部16、及設置在相對於第1環部16的旋轉中心軸的徑向內側的第2環部18。 　　例如，鏈輪主體12，包含：含有鋁的基體20、將基體20的至少局部覆蓋的陽極氧化鋁覆膜22(參考第7圖、第8圖)。 　　[0068] 複數的齒部14與鏈條8卡合。 　　複數的齒部14，從第1環部16的外周，朝相對於旋轉中心軸心C1的徑向外側突出。 　　如第4圖所示，複數的齒部14至少包含：第1齒部24、第2齒部26。在本實施方式，複數的齒部14，包含：複數的第1齒部24、及與第1齒部24同樣數量的第2齒部26；複數的齒部14總共為偶數(例如32、34、36、38任一種)。在本實施方式，第1齒部24、第2齒部26是沿著以旋轉中心軸心C1為中心的圓周上交互排列。第1齒部24及第2齒部26是以等間距排列。第1齒部24，是與鏈條8的一對外連桿片28之間的間隙卡合。第2齒部26，是與鏈條8的一對內連桿片30之間的間隙卡合。 　　[0069] 如第5圖所示，第1齒部24，在旋轉中心軸心方向D1具有第1寬度W1。 　　如第6圖所示，第2齒部26，在旋轉中心軸心方向D1具有較第1寬度W1更小的第2寬度W2。 　　[0070] 第1寬度W1，是表示第1齒部24的旋轉中心軸心方向D1的最大寬度。第2寬度W2，是表示第2齒部26的旋轉中心軸心方向D1的最大寬度。 　　第1寬度W1，大於一對內連桿片30的間隙間隔，且小於一對外連桿片28的間隙間隔。第2寬度W2，小於一對內連桿片30的間隙間隔。 　　[0071] 複數的齒部14包含面向旋轉中心軸心方向D1的側面31。 　　例如第1齒部24具有：與旋轉中心軸心方向D1交叉的一對側面31、31、在其與鏈條8之間傳遞驅動力的驅動面32、驅動面32的相反側的非驅動面33、設置在側面31與驅動面32之間的兩個倒角面34a、設置在側面31與非驅動面33之間的兩個倒角面34b。 　　[0072] 如第7圖所示，第1齒部24的側面31，在包含旋轉中心軸心C1的面切開的剖面觀察，從第1環部16朝向相對於旋轉中心軸心C1的徑向外側而與中心面FC平行地延伸，從中途朝向前端傾斜成漸漸接近中心面FC。所謂中心面FC，是表示鏈輪主體12的第1齒部24的旋轉中心軸心方向D1的距離最內側的面與最外側的面為等距離的面部。 　　[0073] 如第6圖所示，第2齒部26具有：與旋轉中心軸心方向D1交叉的一對側面35、在其與鏈條8之間傳遞驅動力的驅動面36、驅動面36的相反側的非驅動面37、設置在側面35與驅動面36之間的兩個倒角面38a、設置在側面35與非驅動面37之間的兩個倒角面38b。 　　[0074] 如第8圖所示，第2齒部26的側面35，在包含旋轉中心軸心C1的面切開的剖面觀察，從第1環部16朝向相對於旋轉中心軸心C1的徑向外側而與中心面FC平行地延伸，從中途朝向前端傾斜成漸漸接近中心面FC。 　　[0075] 參考第5圖及第6圖，來說明第1齒部24與第2齒部26與鏈條8的卡合狀態。在第5圖及第6圖，省略鏈條8的滾子銷的圖示。 　　如第5圖及第6圖所示，當鏈條8卡合於前鏈輪4時，鏈條8的內連桿片30，位於在相對於旋轉中心軸心C1的周方向鄰接的兩個第1齒部24之間。鏈條8的內連桿片30的內面，在旋轉中心軸心方向D1，位於較第1齒部24的最厚的部位更接近中心面FC。並且第1齒部24的第1寬度W1，大於一對內連桿片30的間隙間隔，所以側面31、31接近外連桿片28的內面。由於鏈條8與複數的齒部14互相卡合成讓之間的軸方向的間隙變小，所以鏈條8當驅動時不易從前鏈輪4脫落。 　　[0076] 參考第1圖，作為與構成複數的齒部14相關的事項，針對複數的齒部14的磨損加以說明。 　　鏈條8相對於前鏈輪4的傾斜角度AG，如上述會因為鏈條8卡合的後鏈輪6的位置而變化。鏈條8的傾斜角度AG變大的話，則鏈條8的外連桿片28與第1齒部24的接觸壓力、及鏈條8的內連桿片30與第2齒部26的接觸壓力會增加，可能會促進第1齒部24及第2齒部26的磨損。由於第1齒部24的側面31接觸於外連桿片28，所以可能讓第1齒部24的側面31的磨損變大。同樣地由於第2齒部26的側面35接觸於外連桿片30，所以可能讓第2齒部26的側面35的磨損變大。而在為了自行車的輕量化而將前鏈輪藉由鋁或鋁合金形成的情況，與鐵等的耐磨損性較高的材料相比，其磨損會變大。磨損量較大時，第1齒部24及第2齒部26與鏈條8之間的軸方向的間隙會變大，所以驅動時的鏈條8的保持力會降低，可能讓鏈條脫落的頻率變高。 　　[0077] 因為這種情形，在本實施方式，複數的齒部14具備如以下的構造(以下稱為「第1構造」)。 　　如第7圖及第8圖所示，複數的齒部14包含：基體40、以及將基體40的至少局部覆蓋，且包含磷及硼的至少其中一方的鍍鎳層42。基體40包含鋁較佳。例如基體40的材質為鋁合金。所謂複數的齒部14，是表示從前鏈輪4中的複數的第1齒部24及複數的第2齒部26所構成的群組中選擇出的兩個以上的齒部。 　　[0078] 鍍鎳層42，形成於第1齒部24及第2齒部26的表面的局部或全部。例如，鍍鎳層42形成於第1齒部24的側面31。例如，鍍鎳層42形成於第2齒部26的側面35。鍍鎳層42也可形成於第1齒部24的驅動面32。鍍鎳層42也可形成於第2齒部26的驅動面36。鍍鎳層42也可形成於第1齒部24的倒角面34a、34b。鍍鎳層42也可形成於第2齒部26的倒角面38a、38b。 　　[0079] 鍍鎳層42，包含磷及硼的至少其中一方。藉此，與不包含這些元素的情況相比可更提高維氏硬度( Vickers hardness)。鍍鎳層42其維氏硬度(Vickers hardness )為500Hv以上較佳。 　　[0080] 例如在鍍鎳層42中包含磷的情況，鍍鎳層42中的磷含有量為0.1質量%以上且10.0質量%以下。鍍鎳層42中的磷含有量較佳為1.0質量%以上且5.0質量%以下。 　　在鍍鎳層42中包含硼的情況，鍍鎳層42中的硼含有量為0.1質量%以上且10.0質量%以下較佳。鍍鎳層42中的硼含有量更佳為0.1質量%以上且2.0質量%以下。 　　[0081] 該鍍鎳層42中包含無電解鍍鎳較佳。 　　鍍鎳層42的厚度為1.0μm以上且100μm以下。鍍鎳層42的厚度更佳為5.0μm以上且40.0μm以下。 　　[0082] 以下說明第1構造的作用。 　　前鏈輪4具有第1齒部24及第2齒部26。第2齒部26的第2寬度W2小於第1齒部24的第1寬度W1。該前鏈輪4其第2齒部26與鏈條8的內連桿片30容易接觸。第1齒部24與鏈條8的外連桿片28容易接觸。尤其鏈條8的傾斜角度變大的話，則接觸頻率及接觸壓力會變高。接觸頻率及接觸壓力較高的情況，第1齒部24及第2齒部26的磨損量會增加。第1齒部24及第2齒部26產生磨損的話，第1齒部24與一對外連桿片28之間的間隙會變大，容易產生鏈條脫落的情形。同樣地，第2齒部26與一對內連桿片30之間的間隙變大，容易產生鏈條脫落的情形。 　　[0083] 本實施方式的前鏈輪4的齒部具備有第1構造。 　　藉由上述第1構造，包含第1齒部24及第2齒部26的複數的齒部14的群組之中至少兩個(複數的齒部14)，包含：基體40、及將基體40的至少局部覆蓋的鍍鎳層42。鍍鎳層42，包含磷及硼的至少其中一方。磷有助提升鍍鎳層42的硬度。硼有助提升鍍鎳層42的硬度。藉由上述構造，能讓複數的齒部14的耐磨損性提升，讓驅動時的鏈條8的保持力提升，可長時間抑制鏈條脫落。 　　[0084] 參考第9圖及第10圖，針對構成第1齒部24的物質，來說明其他構造(以下為「第2構造」)。 　　複數的齒部14包含：基體40、以及設置成將基體40的至少局部覆蓋，且具有硬質粒子43的鍍鎳層44。基體40包含鋁較佳。例如基體40的材質為鋁合金。硬質粒子43分布於鍍鎳之中。所謂複數的齒部14，是表示從前鏈輪4中的複數的第1齒部24及複數的第2齒部26所構成的群組中選擇出的兩個以上的齒部。 　　[0085] 鍍鎳層44，形成於第1齒部24及第2齒部26的表面的局部或全部。例如，鍍鎳層44形成於第1齒部24的側面31。例如，鍍鎳層44形成於第2齒部26的側面35。鍍鎳層44也可形成於第1齒部24的驅動面32。鍍鎳層44也可形成於第2齒部26的驅動面36。鍍鎳層44也可形成於第1齒部24的倒角面34a、34b。鍍鎳層44也可形成於第2齒部26的倒角面38a、38b。 　　[0086] 鍍鎳層44包含硬質粒子43。硬質粒子43相較於藉由鍍鎳所形成的鍍鎳層44，其維氏硬度(Vickers hardness)更高。 　　硬質粒子43，包含氧化鋁及二氧化鋯的至少其中一方。硬質粒子43，也可包含碳化矽、氮化矽等的其他陶瓷。硬質粒子43的維氏硬度(Vickers hardness)為1000Hv以上較佳。 　　硬質粒子43的平均粒徑為0.8μm以上較佳。硬質粒子43的平均粒徑較佳為0.8μm以上3.0μm以下，進一步較佳為0.8μm以上2.0μm以下。平均粒徑表示中值直徑D50。在第9圖所示的鍍鎳層44，為在D50包含1.2μm的氧化鋁的硬質粒子43的例子。在第10圖所示的鍍鎳層44，為在D50包含3.0μm的氧化鋁的硬質粒子43的例子。 　　[0087] 硬質粒子43，設置成相對於與旋轉中心軸心方向D1平行的鍍鎳層44的剖面其面積比為10%以上30%以下較佳。面積比為10%以上15%以下更佳。上述面積比，是表示硬質粒子43相對於鍍鎳層44的剖面的預定區域的面積所占有的面積的比。 　　[0088] 該鍍鎳層44其維氏硬度(Vickers hardness)為500Hv以上較佳。並且鍍鎳層44，可包含磷及硼的至少其中一方。 　　例如在鍍鎳層44中包含磷的情況，鍍鎳層44中的磷含有量為0.1質量%以上且10.0質量%以下。鍍鎳層44中的磷含有量較佳為1.0質量%以上且5.0質量%以下。 　　[0089] 在鍍鎳層44中包含硼的情況，鍍鎳層44中的硼含有量為0.1質量%以上且10.0質量%以下較佳。鍍鎳層44中的硼含有量更佳為0.1質量%以上且2.0質量%以下。 　　[0090] 該等鍍鎳層44中包含無電解鍍鎳較佳。 　　鍍鎳層44的厚度為1.0μm以上且100μm以下。鍍鎳層44的厚度更佳為5.0μm以上且40.0μm以下。 　　[0091] 以下說明第2構造的作用。 　　前鏈輪4，在具有旋轉中心軸心方向D1的寬度不同的第1齒部24及第2齒部26的情況，可能會如上述產生磨損且鏈條容易脫落。針對該情形如上述。 　　[0092] 藉由上述第2構造，包含第1齒部24及第2齒部26的複數的齒部14的群組之中至少兩個(複數的齒部14)，包含：基體40、及鍍鎳層44。鍍鎳層44設置成將基體40的至少局部覆蓋且具有硬質粒子43。硬質粒子43有助提升鍍鎳層44的硬度。藉由上述構造則能提供一種鏈輪，讓其齒部的耐磨損性提升，讓驅動時的鏈條8的保持力提升，可長時間抑制鏈條脫落。 　　[0093] ＜第2實施方式＞ 　　參考第11圖至第14圖，針對本實施方式的後鏈輪50來說明。 　　後鏈輪50為自行車用鏈輪的一種型態。 　　後鏈輪50(自行車用鏈輪)具備有：具有旋轉中心軸心的鏈輪主體51、複數的齒部52、與至少一個變速區域。鏈輪主體51的基體可包含鋁。 　　如第14圖所示，複數的齒部52包含：基體55、及鍍鎳層56。鍍鎳層56設置成將基體55的至少局部覆蓋且具有硬質粒子57。基體55包含鋁較佳。例如基體55的材質為鋁合金。硬質粒子57，可使用上述實施方式所舉例的材料。 　　[0094] 複數的齒部52包含：第1變速齒52a、第2變速齒(省略圖示)、與其他齒部52b。變速區域至少包含：第1變速齒52a、及第2變速齒(省略圖示)。第1變速齒52a，包含用來促進鏈條8的第1換檔的形狀(倒角或凹部)。第2變速齒，包含用來促進鏈條8的第2換檔的形狀。 　　[0095] 如第12圖及第13圖所示，第1變速齒52a，作為用來促進變速的形狀，具有凹部53。第1變速齒52a，其旋轉中心軸心方向D2的中心面FCx，朝後鏈輪50的旋轉中心軸心方向D2的外側(小直徑鏈輪側)換檔。在第1變速齒52a，凹部53，配置於複數的後鏈輪50的排列方向的大直徑鏈輪側(輪轂側)。凹部53構成可供鏈條8的內連桿片30插通的空間。 　　[0096] 藉由該構造，再藉由撥鏈器10將小直徑鏈輪側的力施加於鏈條8的情況，鏈條8的內連桿片30進入凹部53，藉由靠近小直徑鏈輪側的第1變速齒52a使鏈條8靠近小直徑鏈輪側。此時，內連桿片30接觸凹部53，讓鏈條8靠向小直徑鏈輪側。藉此讓鏈條8順暢地進行第1換檔。 　　[0097] 參考第14圖，針對構成第1變速齒52a及第2變速齒(省略圖示)以外的齒部52b(以下稱為驅動齒)的物質加以說明。 　　驅動齒52b，其功能作為用來驅動鏈條8的驅動齒。 　　第1變速齒52a的凹部53，藉由與鏈條8的內連桿片30的接觸，將鏈條8的內連桿片30朝小直徑鏈輪側導引。另一方面，驅動齒52b將力量傳遞到鏈條8。在驅動齒52b產生磨損的話，在變速區域所包含的齒部(例如第1變速齒52a)以外的區域產生變速的可能性變高。 　　[0098] 在本實施方式，至少在驅動齒52b設置鍍鎳層56。可是，也可在包含第1變速齒52a及驅動齒52b之全部複數的齒部52都設置鍍鎳層56。鍍鎳層56，雖然包含第1實施方式說明的第2構造，而也可包含第1構造。藉此，可抑制因鏈條8的接觸導致複數的齒部52b(驅動齒)的磨損。因此，讓齒部52b(驅動齒)的耐磨損性提升，藉由減少第1變速齒52a及第2變速齒以外的複數的齒部52b(驅動齒)的磨損，則能抑制設置在變速區域之外的齒部52b(驅動齒)產生無預期的變速。 　　[0099] ＜第3實施方式＞ 　　參考第15圖，針對本實施方式的前鏈輪組件來說明。前鏈輪組件為自行車用鏈輪組件的一個例子。 　　[0100] 前鏈輪組件60，具備有：第1鏈環61、及較第1鏈環61更小直徑的第2鏈環62。第2鏈環62與第1鏈環61具有共通的旋轉中心軸心C3。 　　[0101] 第1鏈環61具備有：具有旋轉中心軸心C3的鏈輪主體63、及複數的齒部70；複數的齒部70包含：第1齒部64、及在旋轉中心軸心方向具有較第1寬度更小的第2寬度的第2齒部65。 　　第1齒部64如同第1實施方式的構造。第2齒部65如同第1實施方式的構造。例如第1齒部64包含上述的第1構造或第2構造。第2齒部65包含上述的第1構造或第2構造。 　　[0102] 第2鏈環62具備有：鏈輪主體66、與複數的齒部69；上述複數的齒部69包含：在旋轉中心軸心方向具有第3寬度的第3齒部67、及在旋轉中心軸心方向具有較第3寬度更小的第4寬度的第4齒部68。 　　第3齒部67及第4齒部68包含：含有鋁的基體、與將基體的至少局部覆蓋的陽極氧化鋁覆膜(省略圖示)。 　　第3齒部67及第4齒部68，可包含：含有鋁的基體、及將基體的至少局部覆蓋而含有磷及硼的至少其中一方的無電解鍍鎳。例如第3齒部67及第4齒部68的基體的材質為鋁合金。 　　[0103] 第3齒部67及第4齒部68的至少其中一方，包含：陽極氧化鋁覆膜、及含有磷及硼的至少其中一方的無電解鍍鎳的情況，陽極氧化鋁覆膜與無電解鍍鎳在基體設置在不同處。例如，陽極氧化鋁覆膜，設置在第3齒部67的側面及第4齒部68的側面。含有磷及硼的至少其中一方的無電解鍍鎳，設置在第3齒部67的驅動面及第4齒部68的驅動面。 　　[0104] 如第15圖至第17圖所示，第1鏈環61也可具備有：具有旋轉中心軸心C3的鏈輪主體63、複數的齒部70、至少一個變速區域71。 　　[0105] 複數的齒部70，具有：配置於變速區域71的變速齒75、及配置在與變速區域71不同的區域的驅動齒76。 　　變速齒75，表示在相對於旋轉中心軸心C3的周方向配置在與第2釘銷74相同位置及其後方的三個齒部。變速齒75，包含當鏈條8從第2鏈環62朝第1鏈環61換檔變速時，鏈條8最初繞掛的齒部。 　　鍍鎳層78至少形成於驅動齒76。驅動齒76的基體包含鋁較佳。驅動齒76的基體的材質為鋁合金。鍍鎳層78的構造依照第1實施方式所示的例子。例如鍍鎳層78可採取第1構造或第2構造。 　　例如如第16圖所示，複數的驅動齒76包含：基體77、及鍍鎳層78。鍍鎳層78設置成將基體77的至少局部覆蓋且具有硬質粒子79。 　　[0106] 第1鏈環61，包含兩個變速用釘銷(以下稱為第1釘銷73及第2釘銷74)。第1釘銷73及第2釘銷74包含於變速區域。 　　第1釘銷73作成圓柱狀。當鏈條8從第2鏈環62換檔變速到第1鏈環61時，第1釘銷73的側面支承鏈條8。 　　[0107] 如第17圖所示，第2釘銷74作成長圓柱狀。當鏈條8從第2鏈環62換檔變速到第1鏈環61時，第2釘銷74的側面的彎曲面支承鏈條8。 　　[0108] 在第1鏈環61，在相對於旋轉中心軸心C3的徑向且在較第2鏈環62的外周更外側處，設置有第1釘銷73。第2釘銷74配置在相對於旋轉中心軸心C3的徑向且在較第1釘銷73更外側的位置。第1釘銷73及第2釘銷74，在旋轉中心軸心C3配置在外側(第2鏈環62側)。第1釘銷73及第2釘銷74，當變速時，將鏈條8從第2鏈環62換檔變速到第1鏈環61。 　　[0109] 以下說明本實施方式的前鏈輪組件60的作用。 　　第1鏈環61的驅動齒76磨損的話，在磨損處會容易卡住鏈條8或容易脫鏈，也可能在變速區域71以外的部分產生無預期的變速(第1換檔或第2換檔)、或可能鏈條從前鏈輪組件60脫落。 　　[0110] 本實施方式的驅動齒76，至少局部藉由鍍鎳層78所覆蓋。鍍鎳層78包含硬質粒子79。鍍鎳層78，至少形成於驅動齒76，而也可作成形成於全部的複數的齒部70。硬質粒子79有助提升鍍鎳層78的硬度。藉由上述構造，讓驅動齒76的耐磨損性提升，藉由減少驅動齒76的磨損，藉此可抑制在變速區域71之外的驅動齒76產生無預期的變速。 　　[0111] ＜第4實施方式＞ 　　參考第18圖及第19圖，針對本實施方式的前鏈輪80來說明。 　　前鏈輪80包含：鏈輪主體81、複數的齒部82。複數的齒部82包含第1齒部83及第2齒部84。第1齒部83的形狀依照第1實施方式的第1齒部24的形狀。第2齒部84的形狀依照第1實施方式的第2齒部26的形狀。 　　[0112] 複數的齒部82包含：基體85、鍍鎳層86。鍍鎳層86可採取上述第1實施方式所示的第1構造或第2構造。基體85包含：包含第1材料的第1層部87、包含比重與第1材料不同的第2材料的第2層部88、及包含比重較第1材料更小的第3材料的第3層部89。第2材料其比重小於第1材料較佳。 　　[0113] 第1層部87與第2層部88積疊於旋轉中心軸心方向D4。第2層部88與第3層部89積疊於旋轉中心軸心方向D4。第1層部87，在旋轉中心軸心方向D4，積疊於第2層部88與第3層部89之間。 　　[0114] 例如第1材料包含鐵。例如第1材料為各種鋼材、不鏽鋼等。第2材料包含鋁。第3材料包含鋁。鍍鎳層86形成於第2層部88的外表面。鍍鎳層86也可形成於第3層部89的外表面。在該構造的情況，可將複數的齒部82輕量化，且抑制包含鋁的層部的磨損。 　　[0115] ＜第5實施方式＞ 　　參考第20圖及第21圖，針對本實施方式的前鏈輪90來說明。 　　前鏈輪90包含：鏈輪主體91、複數的齒部92。複數的齒部92包含第1齒部93及第2齒部94。第1齒部93的形狀依照第1實施方式的第1齒部24的形狀。第2齒部94的形狀依照第1實施方式的第2齒部26的形狀。 　　[0116] 複數的齒部92包含：基體95、鍍鎳層96。鍍鎳層96可採取上述第1實施方式所示的第1構造或第2構造。基體95，包含：包含第1材料的第1層部97、與包含比重與第1材料不同的第2材料的第2層部98。第2材料其比重小於第1材料較佳。 　　[0117] 第1層部97與第2層部98積疊於旋轉中心軸心方向D5。例如第1材料包含鐵。例如第1材料為各種鋼材、不鏽鋼等。第2材料包含鋁。鍍鎳層96形成於第2層部98的外表面。在該構造的情況，可將複數的齒部92輕量化，且抑制包含鋁的層部的磨損。 　　[0118] (變形例) 　　關於上述各實施方式的說明，是自行車用鏈輪採取的型態的例子，並非意圖限制其形態。本發明，除了上述各實施方式以外，可採取例如以下所示的實施方式的變形例及未相互矛盾的至少兩個變形例組合的型態。 　　[0119] 在各實施方式的鍍鎳層，也可包含磷及硼之外的元素。磷及硼之外的元素的量，可包含在不使鍍鎳層的硬度降低的範圍，較佳為不在500Hv以下的範圍。 　　[0120] 也可在各實施方式的鍍鎳層與基體之間設置黏接層。黏接層為在基體與鍍鎳層兩者之間具有緊貼力的金屬層較佳。 　　[0121] 如第22圖所示，各實施方式的鍍鎳層100可作成雙層構造。例如鍍鎳層100包含：積疊於基體101的第1鍍鎳層102、積疊於第1鍍鎳層102的第2鍍鎳層103。並且也可在第2鍍鎳層103的外表面設置無電解鍍鎳層、其他金屬的鍍層。 　　[0122] 例如第1鍍鎳層102，為不包含磷及硼的層部。第2鍍鎳層103具有第1構造。 　　例如第1鍍鎳層102，為不包含磷及硼的層部。第2鍍鎳層103具有第2構造。 　　例如第1鍍鎳層102具有第1構造。第2鍍鎳層103具有第2構造。 　　例如第1鍍鎳層102具有第2構造。第2鍍鎳層103具有第1構造。 　　例如第1鍍鎳層102，為無電解鍍鎳層。第2鍍鎳層103具有第1構造。 　　例如第1鍍鎳層102，為無電解鍍鎳層。第2鍍鎳層103具有第2構造。 　　[0123] 如第23圖所示，鍍鎳層105可作成三層構造。也就是說，鍍鎳層105包含：積疊於基體106的第1鍍鎳層107、積疊於第1鍍鎳層107的第2鍍鎳層108、積疊於第2鍍鎳層108的第3鍍鎳層109。並且也可在第3鍍鎳層109的外表面設置無電解鍍鎳層、或其他金屬的鍍層。 　　[0124] 例如第1鍍鎳層107，為無電解鍍鎳層。第2鍍鎳層108具有第1構造。第3鍍鎳層109具有第2構造。 　　例如第1鍍鎳層107，為無電解鍍鎳層。第2鍍鎳層108具有第2構造。第3鍍鎳層109具有第1構造。 　　[0125] 在上述第3實施方式，作為配置於變速區域71的變速齒75，是舉例當鏈條8從第2鏈環62換檔變速到第1鏈環61時，鏈條8最初繞掛的齒部。作為變速齒75的其他例子，是舉例當鏈條8從第1鏈環61朝第2鏈環62換檔變速時，鏈條8最初繞掛的齒部。 　　[0126] 作為在上述實施方式顯示的包含前鏈輪4、80、90的組件，例如曲柄組件。曲柄組件至少包含一個前鏈輪4、80、90、曲柄臂、曲柄軸。[0064] <First Embodiment> 　　 With reference to Fig. 1, the operation of the chain when the bicycle is shifted will be described. Figure 1 is a view of the bicycle 2 viewed from above, and is mainly a schematic diagram of the transmission system of the bicycle. The bicycle 2 has at least one type of bicycle sprocket, which is the front sprocket 4, a type of bicycle sprocket, which is the rear sprocket 6, and a chain that is wound around the front sprocket 4 and the rear sprocket 6. 8. Derailleur 10. [0065] In the description of each embodiment, the case where the rear sprocket 6 on which the chain 8 is wound is changed from a predetermined rear sprocket 6 to a rear sprocket 6 having a smaller diameter than the predetermined rear sprocket 6 is referred to as "1st gear shift". The case where the rear sprocket 6 on which the chain 8 is wound is changed from the predetermined rear sprocket 6 to the rear sprocket 6 having a larger diameter than the predetermined rear sprocket 6 is referred to as "second shift".　　[0066] During the first shift and the second shift, the derailleur 10 moves the rear part of the chain 8 in the direction of the rotation center axis Dr of the rear sprocket 6. Specifically, in this embodiment, when the first gear shift is performed, the rear portion of the chain 8 is directed to the right of the rotation center axis direction Dr (the outer direction of the bicycle with respect to the center plane Pb) (the small-diameter rear sprocket 6 )move. At the time of the second shift, the rear portion of the chain 8 moves to the left in the rotation center axis direction Dr (the side of the large-diameter rear sprocket 6).　　 Therefore, the inclination angle AG of the chain 8 will be different because the chain 8 is hung on any rear sprocket 6. The inclination angle AG of the chain 8 represents an angle formed by a plane P1 including the rotation track of the front sprocket 4 and a plane P2 including the track of the chain 8 when the chain 8 is wound around a predetermined rear sprocket 6. The plane P1 and the plane P2 are planes orthogonal to the horizontal plane when the bicycle is erected.　　[0067] With reference to Figs. 2 and 3, the front sprocket 4 of the present embodiment will be described.　　The front sprocket 4 is a single-piece front chain ring in this embodiment. The front sprocket 4 includes a sprocket body 12 having a rotation center axis C1, and plural teeth 14. The sprocket main body 12 includes a first ring portion 16 having a rotation center axis C1 of the front sprocket 4 and a second ring portion 18 provided on the radial inner side with respect to the rotation center axis of the first ring portion 16. "For example, the sprocket body 12 includes a base 20 containing aluminum, and an anodized aluminum film 22 covering at least a part of the base 20 (refer to FIGS. 7 and 8).　　[0068] The plural teeth 14 are engaged with the chain 8. "" Plural tooth portions 14 protrude from the outer periphery of the first ring portion 16 to the radially outer side with respect to the rotation center axis C1. "As shown in FIG. 4, the plurality of teeth 14 includes at least a first tooth 24 and a second tooth 26. In this embodiment, the plurality of teeth 14 includes: a plurality of first teeth 24, and the same number of second teeth 26 as the first teeth 24; the plural teeth 14 are an even number in total (for example, 32, 34 , 36, 38 any one). In the present embodiment, the first tooth portion 24 and the second tooth portion 26 are alternately arranged along a circumference centered on the rotation center axis C1. The first tooth portion 24 and the second tooth portion 26 are arranged at equal intervals. The first tooth portion 24 is engaged with the gap between the pair of link pieces 28 of the chain 8. The second tooth portion 26 is engaged with the gap between the pair of inner link pieces 30 of the chain 8.　　 [0069] As shown in FIG. 5, the first tooth portion 24 has a first width W1 in the rotation center axis direction D1. "As shown in Fig. 6, the second tooth portion 26 has a second width W2 that is smaller than the first width W1 in the rotation center axis direction D1.　　[0070] The first width W1 indicates the maximum width in the rotation center axis direction D1 of the first tooth portion 24. The second width W2 indicates the maximum width in the rotation center axis direction D1 of the second tooth portion 26. "The first width W1" is greater than the gap interval between the pair of inner link pieces 30 and smaller than the gap interval between the pair of outer link pieces 28. The second width W2 is smaller than the gap interval between the pair of inner link pieces 30.　　[0071] The plural teeth 14 include a side surface 31 facing the rotation center axis direction D1. For example, the first tooth portion 24 has a pair of side surfaces 31, 31 intersecting the rotation center axis direction D1, a driving surface 32 that transmits driving force between the tooth portion and the chain 8, and a non-driving surface 33 on the opposite side of the driving surface 32. , Two chamfered surfaces 34a provided between the side surface 31 and the driving surface 32, and two chamfered surfaces 34b provided between the side surface 31 and the non-driving surface 33. [0072] As shown in FIG. 7, the side surface 31 of the first tooth portion 24 is viewed in a cross-section cut on the surface including the rotation center axis C1, from the first ring portion 16 toward the radial direction with respect to the rotation center axis C1 The outer side extends in parallel with the center plane FC, and is inclined from the middle to the front end so as to gradually approach the center plane FC. The center surface FC is a surface in which the innermost surface and the outermost surface of the first tooth portion 24 of the sprocket body 12 are equidistant from each other in the direction D1 of the rotation center axis. [0073] As shown in FIG. 6, the second tooth portion 26 has a pair of side surfaces 35 intersecting the rotation center axis direction D1, a driving surface 36 that transmits driving force between the side surface and the chain 8, and a driving surface 36. The non-driving surface 37 on the opposite side, the two chamfered surfaces 38 a provided between the side surface 35 and the driving surface 36, and the two chamfered surfaces 38 b provided between the side surface 35 and the non-driving surface 37. [0074] As shown in FIG. 8, the side surface 35 of the second tooth portion 26 is viewed in a cross-section cut on a surface including the rotation center axis C1, and is viewed from the first ring portion 16 in a radial direction with respect to the rotation center axis C1. The outer side extends in parallel with the center plane FC, and is inclined from the middle to the front end so as to gradually approach the center plane FC.　　 [0075] With reference to FIGS. 5 and 6, the engagement state of the first tooth portion 24 and the second tooth portion 26 with the chain 8 will be described. In Figs. 5 and 6, illustration of the roller pins of the chain 8 is omitted. As shown in Figs. 5 and 6, when the chain 8 is engaged with the front sprocket 4, the inner link pieces 30 of the chain 8 are located in two adjacent ones in the circumferential direction with respect to the rotation center axis C1. Between the teeth 24. The inner surface of the inner link piece 30 of the chain 8 is located closer to the center surface FC than the thickest part of the first tooth portion 24 in the rotation center axis direction D1. In addition, the first width W1 of the first tooth portion 24 is larger than the gap interval between the pair of inner link pieces 30, so the side surfaces 31 and 31 are close to the inner surface of the outer link piece 28. Since the chain 8 and the plurality of tooth portions 14 are engaged with each other to reduce the axial gap between them, the chain 8 is unlikely to fall off from the front sprocket 4 when it is driven.　　 [0076] With reference to Fig. 1, as matters related to the plural tooth portions 14, the wear of the plural tooth portions 14 will be described.　　 The inclination angle AG of the chain 8 with respect to the front sprocket 4 changes due to the position of the rear sprocket 6 where the chain 8 is engaged, as described above. If the inclination angle AG of the chain 8 increases, the contact pressure between the outer link piece 28 of the chain 8 and the first tooth portion 24 and the contact pressure between the inner link piece 30 of the chain 8 and the second tooth portion 26 will increase. There is a possibility that the wear of the first tooth portion 24 and the second tooth portion 26 may be promoted. Since the side surface 31 of the first tooth portion 24 is in contact with the outer link piece 28, the side surface 31 of the first tooth portion 24 may become more worn. Similarly, since the side surface 35 of the second tooth portion 26 is in contact with the outer link piece 30, the abrasion of the side surface 35 of the second tooth portion 26 may increase. On the other hand, when the front sprocket is formed of aluminum or aluminum alloy in order to reduce the weight of the bicycle, the wear will be greater than that of materials with high wear resistance such as iron. When the amount of wear is large, the axial gap between the first tooth portion 24 and the second tooth portion 26 and the chain 8 will increase, so the holding force of the chain 8 during driving will be reduced, which may cause the frequency of the chain to fall off. high.　　[0077] Because of this situation, in the present embodiment, the plural tooth portions 14 have the following structure (hereinafter referred to as the "first structure"). "As shown in FIGS. 7 and 8, the plurality of teeth 14 includes a base body 40 and a nickel plating layer 42 that covers at least part of the base body 40 and includes at least one of phosphorus and boron. The base 40 preferably contains aluminum. For example, the material of the base body 40 is aluminum alloy. The plural tooth portions 14 indicate two or more tooth portions selected from the group consisting of the plural first tooth portions 24 and the plural second tooth portions 26 in the front sprocket 4.　　[0078] The nickel plating layer 42 is formed on part or all of the surfaces of the first tooth portion 24 and the second tooth portion 26. For example, the nickel plating layer 42 is formed on the side surface 31 of the first tooth portion 24. For example, the nickel plating layer 42 is formed on the side surface 35 of the second tooth portion 26. The nickel plating layer 42 may be formed on the driving surface 32 of the first tooth portion 24. The nickel plating layer 42 may be formed on the driving surface 36 of the second tooth portion 26. The nickel plating layer 42 may be formed on the chamfered surfaces 34 a and 34 b of the first tooth portion 24. The nickel plating layer 42 may be formed on the chamfered surfaces 38a and 38b of the second tooth portion 26.　　[0079] The nickel plating layer 42 includes at least one of phosphorus and boron. As a result, the Vickers hardness (Vickers hardness) can be increased compared to the case where these elements are not included. The nickel-plated layer 42 preferably has a Vickers hardness of 500 Hv or more.　　[0080] For example, when phosphorus is contained in the nickel-plated layer 42, the phosphorus content in the nickel-plated layer 42 is 0.1% by mass or more and 10.0% by mass or less. The phosphorus content in the nickel plating layer 42 is preferably 1.0% by mass or more and 5.0% by mass or less. "When boron is contained in the nickel-plated layer 42, it is preferable that the boron content in the nickel-plated layer 42 is 0.1 mass% or more and 10.0 mass% or less. The boron content in the nickel plating layer 42 is more preferably 0.1% by mass or more and 2.0% by mass or less.　　[0081] The nickel plating layer 42 preferably contains electroless nickel plating. The thickness of the "nickel plating layer 42" is 1.0 μm or more and 100 μm or less. The thickness of the nickel plating layer 42 is more preferably 5.0 μm or more and 40.0 μm or less.　　[0082] The function of the first structure is explained below.　　The front sprocket 4 has a first tooth portion 24 and a second tooth portion 26. The second width W2 of the second tooth portion 26 is smaller than the first width W1 of the first tooth portion 24. The second tooth portion 26 of the front sprocket 4 easily comes into contact with the inner link piece 30 of the chain 8. The first tooth portion 24 easily comes into contact with the outer link piece 28 of the chain 8. In particular, if the inclination angle of the chain 8 increases, the contact frequency and contact pressure will increase. When the contact frequency and contact pressure are high, the wear amount of the first tooth portion 24 and the second tooth portion 26 increases. If the first tooth portion 24 and the second tooth portion 26 are worn, the gap between the first tooth portion 24 and the pair of outer link pieces 28 will increase, and the chain may easily fall off. Similarly, the gap between the second tooth portion 26 and the pair of inner link pieces 30 becomes larger, and the chain is likely to fall off.　　[0083] The tooth portion of the front sprocket 4 of the present embodiment is provided with a first structure. With the above-mentioned first structure, at least two of the group of plural teeth 14 including the first teeth 24 and the second teeth 26 (the plural teeth 14) include: the base 40 and the base 40 The at least partially covered nickel plating layer 42. The nickel plating layer 42 contains at least one of phosphorus and boron. Phosphorus helps to increase the hardness of the nickel plating layer 42. Boron helps to increase the hardness of the nickel plating layer 42. With the above structure, the wear resistance of the plurality of teeth 14 can be improved, the holding force of the chain 8 during driving can be improved, and the chain can be prevented from falling off for a long time.　　 [0084] With reference to Figs. 9 and 10, another structure (hereinafter referred to as "the second structure") will be described with respect to the substance constituting the first tooth portion 24. The plural teeth 14 include a base body 40 and a nickel plating layer 44 provided to cover at least a part of the base body 40 and having hard particles 43. The base 40 preferably contains aluminum. For example, the material of the base body 40 is aluminum alloy. The hard particles 43 are distributed in the nickel plating. The plural tooth portions 14 indicate two or more tooth portions selected from the group consisting of the plural first tooth portions 24 and the plural second tooth portions 26 in the front sprocket 4.　　[0085] The nickel plating layer 44 is formed on part or all of the surfaces of the first tooth portion 24 and the second tooth portion 26. For example, the nickel plating layer 44 is formed on the side surface 31 of the first tooth portion 24. For example, the nickel plating layer 44 is formed on the side surface 35 of the second tooth portion 26. The nickel plating layer 44 may also be formed on the driving surface 32 of the first tooth portion 24. The nickel plating layer 44 may be formed on the driving surface 36 of the second tooth portion 26. The nickel plating layer 44 may be formed on the chamfered surfaces 34 a and 34 b of the first tooth portion 24. The nickel plating layer 44 may be formed on the chamfered surfaces 38a and 38b of the second tooth portion 26.　　[0086] The nickel plating layer 44 contains hard particles 43. The hard particles 43 have a higher Vickers hardness than the nickel plating layer 44 formed by nickel plating. The "hard particles 43" include at least one of alumina and zirconia. The hard particles 43 may also include other ceramics such as silicon carbide and silicon nitride. The Vickers hardness of the hard particles 43 is preferably 1000 Hv or more. The average particle size of the "hard particles 43" is preferably 0.8 μm or more. The average particle diameter of the hard particles 43 is preferably 0.8 μm or more and 3.0 μm or less, and more preferably 0.8 μm or more and 2.0 μm or less. The average particle diameter represents the median diameter D50. The nickel plating layer 44 shown in FIG. 9 is an example of hard particles 43 containing 1.2 μm aluminum oxide in D50. The nickel plating layer 44 shown in FIG. 10 is an example of hard particles 43 containing 3.0 μm alumina in D50.　　[0087] The hard particles 43 are preferably arranged so that the area ratio of the nickel plating layer 44 parallel to the rotation center axis direction D1 is 10% or more and 30% or less. The area ratio is more preferably 10% or more and 15% or less. The above-mentioned area ratio indicates the ratio of the area occupied by the hard particles 43 with respect to the area of the predetermined area of the cross section of the nickel plating layer 44.　　[0088] The Vickers hardness of the nickel-plated layer 44 is preferably 500Hv or more. In addition, the nickel plating layer 44 may include at least one of phosphorus and boron. "For example, when phosphorus is contained in the nickel plating layer 44, the phosphorus content in the nickel plating layer 44 is 0.1 mass% or more and 10.0 mass% or less. The phosphorus content in the nickel plating layer 44 is preferably 1.0% by mass or more and 5.0% by mass or less.　　[0089] When boron is contained in the nickel-plated layer 44, the boron content in the nickel-plated layer 44 is preferably 0.1% by mass or more and 10.0% by mass or less. The boron content in the nickel plating layer 44 is more preferably 0.1% by mass or more and 2.0% by mass or less.　　[0090] The nickel plating layer 44 preferably contains electroless nickel plating. The thickness of the "nickel plating layer 44" is 1.0 μm or more and 100 μm or less. The thickness of the nickel plating layer 44 is more preferably 5.0 μm or more and 40.0 μm or less.　　[0091] The function of the second structure is explained below. When the front sprocket 4 has a first tooth portion 24 and a second tooth portion 26 with different widths in the rotation center axis direction D1, wear may occur as described above and the chain may easily fall off. This situation is as described above. [0092] With the second structure described above, at least two of the group of plural teeth 14 including the first teeth 24 and the second teeth 26 (the plural teeth 14) include: a base 40, and Nickel-plated layer 44. The nickel plating layer 44 is provided to cover at least a part of the base body 40 and has hard particles 43. The hard particles 43 help to increase the hardness of the nickel plating layer 44. With the above structure, it is possible to provide a sprocket that improves the wear resistance of its teeth, improves the holding force of the chain 8 during driving, and can prevent the chain from falling off for a long time.　　[0093] <Second Embodiment> 　　 With reference to Figs. 11 to 14, the rear sprocket 50 of the present embodiment will be described.　　The rear sprocket 50 is a type of bicycle sprocket. The rear sprocket 50 (a bicycle sprocket) is provided with a sprocket main body 51 having a rotation center axis, a plurality of teeth 52, and at least one speed change area. The base of the sprocket main body 51 may include aluminum.　　 As shown in FIG. 14, the plurality of teeth 52 includes a base body 55 and a nickel plating layer 56. The nickel plating layer 56 is provided to cover at least a part of the base 55 and has hard particles 57. The base 55 preferably contains aluminum. For example, the material of the base 55 is aluminum alloy. For the hard particles 57, the materials exemplified in the above embodiments can be used.　　[0094] The plural teeth 52 include a first gear 52a, a second gear (not shown), and other gears 52b. The speed change area includes at least a first speed change tooth 52a and a second speed change tooth (not shown). The first gear 52a includes a shape (chamfer or recess) for facilitating the first shift of the chain 8. The second shift tooth includes a shape for facilitating the second shift of the chain 8.　　[0095] As shown in FIGS. 12 and 13, the first shift tooth 52a has a recess 53 as a shape for accelerating shifting. The first gear 52a shifts gears on the center surface FCx in the rotation center axis direction D2 of the rear sprocket 50 in the rotation center axis direction D2 (the small-diameter sprocket side). In the first gear 52a, the recess 53 is arranged on the large-diameter sprocket side (hub side) in the arrangement direction of the plural rear sprockets 50. The recess 53 constitutes a space through which the inner link piece 30 of the chain 8 can be inserted. [0096] With this structure, when the force on the side of the small-diameter sprocket is applied to the chain 8 by the derailleur 10, the inner link piece 30 of the chain 8 enters the concave portion 53, by approaching the side of the small-diameter sprocket. The first gear 52a of the gear shifts the chain 8 closer to the side of the small-diameter sprocket. At this time, the inner link piece 30 contacts the recessed portion 53, so that the chain 8 is brought to the side of the small-diameter sprocket. This allows the chain 8 to perform the first shift smoothly.　　[0097] With reference to Fig. 14, the material constituting the tooth portion 52b (hereinafter referred to as the drive tooth) other than the first shift tooth 52a and the second shift tooth (not shown) will be described. The "driving tooth 52b" functions as a driving tooth for driving the chain 8. "The recess 53 of the first gear 52a guides the inner link piece 30 of the chain 8 to the side of the small-diameter sprocket by contact with the inner link piece 30 of the chain 8". On the other hand, the driving tooth 52b transmits power to the chain 8. If wear occurs in the drive teeth 52b, there is a high possibility of shifting in areas other than the teeth included in the shifting area (for example, the first shifting teeth 52a).　　[0098] In this embodiment, at least the drive tooth 52b is provided with a nickel plating layer 56. However, the nickel plating layer 56 may be provided on all the plural tooth portions 52 including the first shift teeth 52a and the drive teeth 52b. Although the nickel plating layer 56 includes the second structure described in the first embodiment, it may include the first structure. Thereby, it is possible to suppress the wear of the plural tooth portions 52b (driving teeth) due to the contact of the chain 8. Therefore, the wear resistance of the teeth 52b (drive teeth) is improved, and the wear of the plural teeth 52b (drive teeth) other than the first gear 52a and the second gear can be suppressed. The tooth portion 52b (drive tooth) outside the area causes unexpected shifting.　　[0099] <3rd embodiment> 　　 With reference to Fig. 15, the front sprocket assembly of this embodiment will be described. The front sprocket assembly is an example of a bicycle sprocket assembly.　　[0100] The front sprocket assembly 60 includes a first link 61 and a second link 62 having a smaller diameter than the first link 61. The second link 62 and the first link 61 have a common rotation center axis C3. [0101] The first link 61 is provided with a sprocket body 63 having a rotation center axis C3, and a plurality of teeth 70; the plurality of teeth 70 includes a first tooth 64 and the direction of the rotation center axis The second tooth portion 65 has a second width smaller than the first width. ""The structure of the first tooth portion 64 is the same as that of the first embodiment. The second tooth 65 has the same structure as the first embodiment. For example, the first tooth portion 64 includes the first structure or the second structure described above. The second tooth portion 65 includes the above-mentioned first structure or second structure. [0102] The second link 62 includes a sprocket body 66 and a plurality of teeth 69; the plurality of teeth 69 includes: a third tooth 67 having a third width in the direction of the rotation center axis, and a The rotation center axis direction has a fourth tooth portion 68 having a fourth width smaller than the third width. ""The 3rd tooth part 67 and the 4th tooth part 68 contain the base body containing aluminum, and the anodized aluminum film (illustration omitted) which covers at least part of the base body. ""The third tooth portion 67 and the fourth tooth portion 68 may include: a matrix containing aluminum, and electroless nickel plating that covers at least part of the matrix and contains at least one of phosphorus and boron. For example, the material of the base of the third tooth portion 67 and the fourth tooth portion 68 is aluminum alloy. [0103] At least one of the third tooth portion 67 and the fourth tooth portion 68 includes an anodic aluminum oxide coating and an electroless nickel plating containing at least one of phosphorus and boron, an anodic aluminum oxide coating and Electroless nickel plating is arranged in different places on the substrate. For example, an anodized aluminum film is provided on the side surface of the third tooth portion 67 and the side surface of the fourth tooth portion 68. Electroless nickel plating containing at least one of phosphorus and boron is provided on the driving surface of the third tooth portion 67 and the driving surface of the fourth tooth portion 68.　　[0104] As shown in FIGS. 15 to 17, the first link 61 may be provided with a sprocket body 63 having a rotation center axis C3, a plurality of teeth 70, and at least one shift region 71.　　[0105] The plural tooth portions 70 have a shift tooth 75 arranged in the shift region 71 and a drive tooth 76 arranged in a region different from the shift region 71. The "shift tooth 75" indicates three tooth portions arranged at the same position as the second pin 74 and behind it in the circumferential direction with respect to the rotation center axis C3. The gear 75 includes a tooth portion that the chain 8 is initially wound around when the chain 8 is shifted from the second link 62 to the first link 61 for gear shifting. The “nickel plating layer 78” is formed at least on the driving teeth 76. The base of the driving tooth 76 preferably contains aluminum. The material of the base of the driving tooth 76 is aluminum alloy. The structure of the nickel plating layer 78 conforms to the example shown in the first embodiment. For example, the nickel plating layer 78 may take the first structure or the second structure. "" For example, as shown in FIG. 16, the plurality of driving teeth 76 includes a base body 77 and a nickel plating layer 78. The nickel plating layer 78 is provided to cover at least a part of the base body 77 and has hard particles 79.　　[0106] The first link 61 includes two shift pins (hereinafter referred to as the first pin 73 and the second pin 74). The first pin 73 and the second pin 74 are included in the shifting area.　　The first pin 73 is formed in a cylindrical shape. When the chain 8 is shifted from the second link 62 to the first link 61, the side surface of the first pin 73 supports the chain 8.　　[0107] As shown in Fig. 17, the second pin 74 is formed in a long cylindrical shape. When the chain 8 is shifted from the second link 62 to the first link 61, the curved surface of the side surface of the second pin 74 supports the chain 8.　　[0108] The first link 61 is provided with a first pin 73 in the radial direction with respect to the rotation center axis C3 and on the outside of the outer periphery of the second link 62. The second pin 74 is arranged in a radial direction with respect to the rotation center axis C3 and at a position outside the first pin 73. The first pin 73 and the second pin 74 are arranged outside (the second link 62 side) on the rotation center axis C3. The first pin 73 and the second pin 74 shift the chain 8 from the second link 62 to the first link 61 when the gear is shifted.　　[0109] Hereinafter, the function of the front sprocket assembly 60 of the present embodiment will be described. If the drive teeth 76 of the first link 61 are worn out, the chain 8 may be easily caught or disconnected at the worn area, and unexpected shifting may occur in parts other than the shifting area 71 (first gear shift or second gear shift). ), or the chain may fall off from the front sprocket assembly 60.　　[0110] The driving teeth 76 of this embodiment are at least partially covered by the nickel plating layer 78. The nickel plating layer 78 contains hard particles 79. The nickel plating layer 78 is formed at least on the driving teeth 76, but may be formed on all the plural teeth 70. The hard particles 79 help increase the hardness of the nickel plating layer 78. With the above structure, the wear resistance of the drive teeth 76 is improved, and by reducing the wear of the drive teeth 76, the drive teeth 76 outside the shifting area 71 can be restrained from unexpectedly shifting.　　[0111] <Fourth Embodiment> 　　 With reference to Figs. 18 and 19, the front sprocket 80 of the present embodiment will be described. The front sprocket 80 includes a sprocket body 81 and a plurality of teeth 82. The plural tooth portions 82 include a first tooth portion 83 and a second tooth portion 84. The shape of the first tooth portion 83 conforms to the shape of the first tooth portion 24 of the first embodiment. The shape of the second tooth portion 84 conforms to the shape of the second tooth portion 26 of the first embodiment.　　[0112] The plural teeth 82 include a base 85 and a nickel-plated layer 86. The nickel plating layer 86 may take the first structure or the second structure shown in the first embodiment described above. The base 85 includes: a first layer portion 87 including a first material, a second layer portion 88 including a second material having a different specific gravity from the first material, and a third layer including a third material having a smaller specific gravity than the first material部89. The second material preferably has a smaller specific gravity than the first material.　　[0113] The first layer portion 87 and the second layer portion 88 are stacked in the rotation center axis direction D4. The second layer portion 88 and the third layer portion 89 are stacked in the rotation center axis direction D4. The first layer portion 87 is stacked between the second layer portion 88 and the third layer portion 89 in the rotation center axis direction D4.　　[0114] For example, the first material includes iron. For example, the first material is various steel materials, stainless steel, and the like. The second material contains aluminum. The third material contains aluminum. The nickel plating layer 86 is formed on the outer surface of the second layer portion 88. The nickel plating layer 86 may be formed on the outer surface of the third layer portion 89. In the case of this structure, the weight of the plurality of teeth 82 can be reduced, and the wear of the layer including aluminum can be suppressed.　　[0115] <Fifth Embodiment> 　　 With reference to Figs. 20 and 21, the front sprocket 90 of the present embodiment will be described.　　The front sprocket 90 includes a sprocket main body 91 and a plurality of teeth 92. The plural tooth portions 92 include a first tooth portion 93 and a second tooth portion 94. The shape of the first tooth portion 93 conforms to the shape of the first tooth portion 24 of the first embodiment. The shape of the second tooth portion 94 conforms to the shape of the second tooth portion 26 of the first embodiment.　　[0116] The plural teeth 92 include a base 95 and a nickel-plated layer 96. The nickel plating layer 96 may take the first structure or the second structure shown in the first embodiment described above. The base 95 includes a first layer portion 97 including a first material, and a second layer portion 98 including a second material having a specific gravity different from the first material. The second material preferably has a smaller specific gravity than the first material.　　[0117] The first layer portion 97 and the second layer portion 98 are stacked in the rotation center axis direction D5. For example, the first material contains iron. For example, the first material is various steel materials, stainless steel, and the like. The second material contains aluminum. The nickel plating layer 96 is formed on the outer surface of the second layer portion 98. In the case of this structure, the weight of the plurality of teeth 92 can be reduced, and the abrasion of the layer including aluminum can be suppressed.　　[0118] (Modifications) 　　 The descriptions of the above-mentioned embodiments are examples of the types of bicycle sprockets, and are not intended to limit the types. In addition to the above-mentioned respective embodiments, the present invention may take, for example, a combination of the following modifications of the embodiment and at least two modifications that are not inconsistent with each other.　　[0119] The nickel plating layer of each embodiment may contain elements other than phosphorus and boron. The amount of elements other than phosphorus and boron may be included in a range that does not reduce the hardness of the nickel plating layer, and is preferably not in the range of 500 Hv or less.　　[0120] An adhesive layer may be provided between the nickel plating layer and the substrate of each embodiment. The adhesive layer is preferably a metal layer with close adhesion between the substrate and the nickel-plated layer.　　[0121] As shown in FIG. 22, the nickel plating layer 100 of each embodiment can be made into a two-layer structure. For example, the nickel-plated layer 100 includes a first nickel-plated layer 102 stacked on the base 101 and a second nickel-plated layer 103 stacked on the first nickel-plated layer 102. In addition, an electroless nickel plating layer or a plating layer of other metals may be provided on the outer surface of the second nickel plating layer 103.　　[0122] For example, the first nickel plating layer 102 is a layer that does not contain phosphorus and boron. The second nickel plating layer 103 has a first structure. "" For example, the first nickel plating layer 102 is a layer that does not contain phosphorus and boron. The second nickel plating layer 103 has a second structure. "" For example, the first nickel plating layer 102 has a first structure. The second nickel plating layer 103 has a second structure. "" For example, the first nickel plating layer 102 has a second structure. The second nickel plating layer 103 has a first structure. "" For example, the first nickel plating layer 102 is an electroless nickel plating layer. The second nickel plating layer 103 has a first structure. "" For example, the first nickel plating layer 102 is an electroless nickel plating layer. The second nickel plating layer 103 has a second structure.　　[0123] As shown in Fig. 23, the nickel plating layer 105 can be made into a three-layer structure. That is, the nickel-plated layer 105 includes: a first nickel-plated layer 107 stacked on the base 106, a second nickel-plated layer 108 stacked on the first nickel-plated layer 107, and a second nickel-plated layer 108 stacked on The third nickel plating layer 109. In addition, an electroless nickel plating layer or a plating layer of other metals may be provided on the outer surface of the third nickel plating layer 109.　　[0124] For example, the first nickel plating layer 107 is an electroless nickel plating layer. The second nickel plating layer 108 has a first structure. The third nickel plating layer 109 has a second structure. "" For example, the first nickel plating layer 107 is an electroless nickel plating layer. The second nickel plating layer 108 has a second structure. The third nickel plating layer 109 has a first structure. [0125] In the third embodiment described above, as the gearshift teeth 75 arranged in the gearshift region 71, when the chain 8 is shifted from the second link 62 to the first link 61, the chain 8 is initially wound around the gear. Department. As another example of the shift tooth 75, when the chain 8 is shifted from the first link 61 to the second link 62, the chain 8 is initially wound around the tooth.　　[0126] As the component including the front sprockets 4, 80, 90 shown in the above embodiment, for example, a crank component. The crank assembly includes at least one front sprocket 4, 80, 90, crank arm, and crank shaft.

[0127]AG‧‧‧傾斜角度C1‧‧‧旋轉中心軸心C3‧‧‧旋轉中心軸心D1‧‧‧旋轉中心軸心方向D2‧‧‧旋轉中心軸心方向D4‧‧‧旋轉中心軸心方向D5‧‧‧旋轉中心軸心方向Dr‧‧‧旋轉中心軸心方向FC‧‧‧中心面FCx‧‧‧中心面P1‧‧‧平面P2‧‧‧平面Pb‧‧‧中心面W1‧‧‧第1寬度W2‧‧‧第2寬度2‧‧‧自行車4‧‧‧前鏈輪6‧‧‧後鏈輪8‧‧‧鏈條10‧‧‧撥鏈器12‧‧‧鏈輪主體14‧‧‧齒部16‧‧‧第1環部18‧‧‧第2環部20‧‧‧基體22‧‧‧陽極氧化鋁覆膜24‧‧‧第1齒部26‧‧‧第2齒部28‧‧‧外連桿片30‧‧‧內連桿片31‧‧‧側面32‧‧‧驅動面33‧‧‧非驅動面34a‧‧‧倒角面34b‧‧‧倒角面35‧‧‧側面36‧‧‧驅動面37‧‧‧非驅動面38a‧‧‧倒角面38b‧‧‧倒角面40‧‧‧基體42‧‧‧鍍鎳層43‧‧‧硬質粒子44‧‧‧鍍鎳層50‧‧‧後鏈輪51‧‧‧鏈輪主體52‧‧‧齒部52a‧‧‧第1變速齒52b‧‧‧驅動齒53‧‧‧凹部55‧‧‧基體56‧‧‧鍍鎳層57‧‧‧硬質粒子60‧‧‧前鏈輪組件61‧‧‧第1鏈環62‧‧‧第2鏈環63‧‧‧鏈輪主體64‧‧‧第1齒部65‧‧‧第2齒部66‧‧‧鏈輪主體67‧‧‧第3齒部68‧‧‧第4齒部70‧‧‧齒部71‧‧‧變速區域75‧‧‧變速齒73‧‧‧第1釘銷74‧‧‧第2釘銷76‧‧‧驅動齒77‧‧‧基體78‧‧‧鍍鎳層79‧‧‧硬質粒子80‧‧‧前鏈輪81‧‧‧鏈輪主體82‧‧‧齒部83‧‧‧第1齒部84‧‧‧第2齒部85‧‧‧基體86‧‧‧鍍鎳層87‧‧‧第1層部88‧‧‧第2層部89‧‧‧第3層部90‧‧‧前鏈輪91‧‧‧鏈輪主體92‧‧‧齒部93‧‧‧第1齒部94‧‧‧第2齒部95‧‧‧基體96‧‧‧鍍鎳層97‧‧‧第1層部98‧‧‧第2層部100‧‧‧鍍鎳層101‧‧‧基體102‧‧‧第1鍍鎳層103‧‧‧第2鍍鎳層105‧‧‧鍍鎳層106‧‧‧基體107‧‧‧第1鍍鎳層108‧‧‧第2鍍鎳層109‧‧‧第3鍍鎳層[0127]AG‧‧‧Inclination Angle C1‧‧‧Rotation Center Axis C3‧‧‧Rotation Center Axis D1‧‧‧Rotation Center Axis Direction D2‧‧‧Rotation Center Axis Direction D4‧‧‧Rotation Center Axis Center direction D5‧‧‧Rotation center axis direction Dr. ‧‧First width W2‧‧‧Second width2‧‧‧Bicycle 4‧‧‧Front sprocket 6‧‧‧Rear sprocket 8‧‧‧Chain 10‧‧‧Derailleur 12‧‧‧Sprocket body 14‧‧‧Tooth 16‧‧‧First ring 18‧‧‧Second ring 20‧‧‧Matrix 22‧‧‧Anodized aluminum coating 24‧‧‧First tooth 26‧‧‧Second Tooth 28‧‧‧Outer connecting rod piece 30‧‧‧Inner connecting rod piece 31‧‧‧Side surface 32‧‧‧Drive surface 33‧‧‧Non-drive surface 34a‧‧‧Chamfered surface 34b‧‧‧Chamfered surface 35‧‧‧Side surface 36‧‧‧Drive surface 37‧‧‧Non-drive surface 38a‧‧‧Chamfered surface 38b‧‧‧Chamfered surface 40‧‧‧Matrix 42‧‧‧Nickel-plated layer 43‧‧‧Hard particles 44. Base 56‧‧‧Nickel plating 57‧‧‧Hard particles 60‧‧‧Front sprocket assembly 61‧‧‧First chain 62‧‧‧Second chain 63‧‧‧Sprocket main body 64‧‧‧ 1 tooth 65‧‧‧2nd tooth 66‧‧‧Sprocket main body 67‧‧‧3rd tooth 68‧‧‧4th tooth 70‧‧‧tooth 71‧‧‧shift area 75‧‧‧ Shift gear 73‧‧‧First pin 74‧‧‧Second pin 76‧‧‧Drive tooth 77‧‧‧Base 78‧‧‧Nickel-plated layer 79‧‧‧Hard particles 80‧‧‧Front sprocket 81 ‧‧‧Sprocket main body 82‧‧‧Tooth part 83‧‧‧First tooth part 84‧‧‧Second tooth part 85‧‧‧Base 86‧‧‧Nickel-plated layer 87‧‧‧First layer part 88‧ ‧‧Second layer 89‧‧‧3rd layer 90‧‧‧Front sprocket 91‧‧‧Sprocket main body 92‧‧‧Tooth part 93‧‧‧First tooth part 94‧‧‧Second tooth part 95‧‧‧Substrate 96‧‧‧Nickel-plated layer 97‧‧‧First layer 98‧‧‧Second layer 100‧‧‧Nickel-plated layer 101 ‧‧‧Second nickel-plated layer 105‧‧‧Nickel-plated layer 106‧‧‧Matrix 107‧‧‧First nickel-plated layer 108‧‧‧Second nickel-plated layer 109‧‧‧Third nickel-plated layer

[0063] 　　第1圖為自行車的傳動系統的示意圖。 　　第2圖是第1實施方式的前鏈輪的側視圖。 　　第3圖是第1實施方式的前鏈輪的立體圖。 　　第4圖是第1實施方式的前鏈輪的局部放大圖。 　　第5圖是第1齒部的俯視圖。 　　第6圖是第2齒部的俯視圖。 　　第7圖為從第5圖的7-7線觀察的剖面圖。 　　第8圖為從第6圖的8-8線觀察的剖面圖。 　　第9圖為鍍鎳層的第2構造的一個例子的電子顯微鏡照片圖。 　　第10圖為鍍鎳層的第2構造的其他例子的電子顯微鏡照片圖。 　　第11圖是針對第2實施方式的後鏈輪，第1變速齒的面向小直徑鏈輪側的側視圖。 　　第12圖是針對第2實施方式的後鏈輪的第1變速齒的俯視圖。 　　第13圖是針對第2實施方式的後鏈輪，第1變速齒的面向大直徑鏈輪側的側視圖。 　　第14圖是針對第2實施方式的後鏈輪，第1變速齒及第2變速齒以外的齒部的剖面圖。 　　第15圖是第3實施方式的前鏈輪的側視圖。 　　第16圖是齒部的剖面圖。 　　第17圖是第2變速齒的立體圖。 　　第18圖是針對第4實施方式的後鏈輪的第1齒部的剖面圖。 　　第19圖是針對第4實施方式的後鏈輪的第2齒部的剖面圖。 　　第20圖是針對第5實施方式的後鏈輪的第1齒部的剖面圖。 　　第21圖是針對第5實施方式的後鏈輪的第2齒部的剖面圖。 　　第22圖是其他實施方式的鍍鎳層的剖面圖。 　　第23圖是其他實施方式的鍍鎳層的剖面圖。[0063] "Figure 1" is a schematic diagram of a bicycle transmission system.　　 Figure 2 is a side view of the front sprocket of the first embodiment.　　 Figure 3 is a perspective view of the front sprocket of the first embodiment. "Figure 4" is a partial enlarged view of the front sprocket of the first embodiment.　　 Figure 5 is a plan view of the first tooth.　　 Figure 6 is a plan view of the second tooth portion.　　 Figure 7 is a cross-sectional view taken from line 7-7 of Figure 5.　　 Figure 8 is a cross-sectional view taken from line 8-8 of Figure 6.　　 Figure 9 is an electron micrograph of an example of the second structure of the nickel-plated layer.　　 Figure 10 is an electron micrograph of another example of the second structure of the nickel-plated layer.　　 Figure 11 is a side view of the rear sprocket according to the second embodiment, with the first shift tooth facing the small-diameter sprocket. "Figure 12" is a plan view of the first gear change of the rear sprocket of the second embodiment.　　 Figure 13 is a side view of the rear sprocket according to the second embodiment, with the first transmission tooth facing the large-diameter sprocket. "Figure 14" is a cross-sectional view of the rear sprocket according to the second embodiment, with teeth other than the first gear and the second gear.　　 Figure 15 is a side view of the front sprocket of the third embodiment.　　 Figure 16 is a cross-sectional view of the tooth.　　 Figure 17 is a perspective view of the second gear change. "Figure 18" is a cross-sectional view of the first tooth portion of the rear sprocket according to the fourth embodiment.　　 Figure 19 is a cross-sectional view of the second tooth portion of the rear sprocket according to the fourth embodiment.　　 Figure 20 is a cross-sectional view of the first tooth portion of the rear sprocket according to the fifth embodiment.　　 Figure 21 is a cross-sectional view of the second tooth portion of the rear sprocket according to the fifth embodiment.　　 Figure 22 is a cross-sectional view of a nickel plating layer in another embodiment.　　 Figure 23 is a cross-sectional view of a nickel plating layer in another embodiment.

12‧‧‧鏈輪主體 12‧‧‧Sprocket body

14‧‧‧齒部 14‧‧‧Tooth

20‧‧‧基體 20‧‧‧Matrix

22‧‧‧陽極氧化鋁覆膜 22‧‧‧Anodic aluminum oxide film

24‧‧‧第1齒部 24‧‧‧First tooth

31‧‧‧側面 31‧‧‧Side

40‧‧‧基體 40‧‧‧Matrix

42‧‧‧鍍鎳層 42‧‧‧Nickel plating

FC‧‧‧中心面 FC‧‧‧Center plane

D1‧‧‧旋轉中心軸心方向 D1‧‧‧Rotation center axis direction

Claims (27)

一種自行車用鏈輪，具備有：具有旋轉中心軸心的鏈輪主體、與複數的齒部；上述複數的齒部包含：在上述旋轉中心軸心方向具有第1寬度的第1齒部、及在上述旋轉中心軸心方向具有較上述第1寬度更小的第2寬度的第2齒部；上述複數的齒部包含：基體、以及將上述基體的至少局部覆蓋且包含硼的鍍鎳層；上述鍍鎳層中的硼含有量為0.1質量%以上且10.0質量%以下。 A bicycle sprocket, comprising: a sprocket body having a rotation center axis, and a plurality of teeth; the plurality of teeth include: a first tooth having a first width in the direction of the rotation center axis, and A second tooth portion having a second width smaller than the first width in the axis direction of the rotation center; the plurality of tooth portions include: a base, and a nickel plating layer that covers at least part of the base and contains boron; The boron content in the nickel plating layer is 0.1% by mass or more and 10.0% by mass or less. 一種自行車用鏈輪，具備有：具有旋轉中心軸心的鏈輪主體、與複數的齒部；上述複數的齒部包含：在上述旋轉中心軸心方向具有第1寬度的第1齒部、及在上述旋轉中心軸心方向具有較上述第1寬度更小的第2寬度的第2齒部；上述複數的齒部包含：基體、以及設置成將上述基體的至少局部覆蓋且具有硬質粒子的鍍鎳層；上述硬質粒子，包含氧化鋁及二氧化鋯的至少其中一方；上述硬質粒子，設置成相對於與旋轉中心軸心方向平行的上述鍍鎳層的剖面，面積比為10%以上30%以下。 A bicycle sprocket, comprising: a sprocket body having a rotation center axis, and a plurality of teeth; the plurality of teeth include: a first tooth having a first width in the direction of the rotation center axis, and There is a second tooth portion having a second width smaller than the first width in the axis direction of the rotation center; Nickel layer; the hard particles include at least one of aluminum oxide and zirconium dioxide; the hard particles are provided with respect to the cross section of the nickel-plated layer parallel to the axis of the rotation center, with an area ratio of 10% or more and 30% the following. 一種自行車用鏈輪，具備有：具有旋轉中心軸心的鏈輪主體、複數的齒部、與至少一個變速區域；上述複數的齒部包含：基體、以及設置成將上述基體的至少局部覆蓋且具有硬質粒子的鍍鎳層；上述硬質粒子，包含氧化鋁及二氧化鋯的至少其中一方；上述硬質粒子，設置成相對於與旋轉中心軸心方向平行的上述鍍鎳層的剖面，面積比為10%以上30%以下。 A bicycle sprocket, comprising: a sprocket body having a central axis of rotation, a plurality of teeth, and at least one shifting area; the plurality of teeth includes a base body, and a base body, and a base body provided to cover at least a part of the base body A nickel-plated layer with hard particles; the hard particles include at least one of aluminum oxide and zirconium dioxide; the hard particles are arranged so as to have an area ratio with respect to the cross-section of the nickel-plated layer parallel to the axis of the rotation center More than 10% and less than 30%. 如申請專利範圍第3項的自行車用鏈輪，其中，上述複數的齒部具有：配置於上述變速區域的變速齒、及配置在與上述變速區域不同的區域的驅動齒；上述鍍鎳層至少形成於上述驅動齒。 For example, the bicycle sprocket according to the third item of the scope of patent application, wherein the plurality of teeth have: shift teeth arranged in the shift region, and drive teeth arranged in a region different from the shift region; and the nickel plating layer is at least It is formed in the above-mentioned driving tooth. 如申請專利範圍第1或2項的自行車用鏈輪，其中，上述複數的齒部，包含面向上述旋轉中心軸心方向的側面，上述鍍鎳層形成於上述第1齒部的側面。 For example, the bicycle sprocket according to claim 1 or 2, wherein the plurality of teeth include side surfaces facing the rotation center axis direction, and the nickel-plated layer is formed on the side surface of the first tooth. 如申請專利範圍第1或2項的自行車用鏈輪，其中，上述複數的齒部，包含面向上述旋轉中心軸心方向的側面，上述鍍鎳層形成於上述第2齒部的側面。 For example, the bicycle sprocket according to claim 1 or 2, wherein the plurality of teeth include side surfaces facing the axis of the rotation center, and the nickel-plated layer is formed on the side surface of the second tooth. 如申請專利範圍第2、3及4項中任一項的自行車用鏈輪，其中，上述硬質粒子的平均粒徑為0.8μm以上。 For example, the bicycle sprocket according to any one of items 2, 3, and 4 of the scope of patent application, wherein the average particle size of the hard particles is 0.8 μm or more. 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述基體包含：包含第1材料的第1層部、及包含比重與上述第1材料不同的第2材料的第2層部。 For example, the bicycle sprocket according to any one of items 1 to 4 in the scope of the patent application, wherein the base body includes: a first layer portion including a first material, and a second material including a second material having a different specific gravity from the first material. 2nd floor department. 如申請專利範圍第8項的自行車用鏈輪，其中，上述第2材料，其比重小於上述第1材料，上述第1層部與第2層部，積疊於上述旋轉中心軸心方向。 For example, the bicycle sprocket according to claim 8, wherein the second material has a smaller specific gravity than the first material, and the first layer portion and the second layer portion are stacked in the direction of the rotation center axis. 如申請專利範圍第8項的自行車用鏈輪，其中，上述第1材料包含鐵，上述第2材料包含鋁。 For example, the bicycle sprocket according to item 8 of the scope of patent application, wherein the first material includes iron, and the second material includes aluminum. 如申請專利範圍第8項的自行車用鏈輪，其中，上述鍍鎳層形成於上述第2層部的外表面。 For example, the bicycle sprocket according to item 8 of the scope of patent application, wherein the nickel-plated layer is formed on the outer surface of the second layer portion. 如申請專利範圍第8項的自行車用鏈輪，其中，上述基體包含第3層部，第3層部包含比重較第1材料更小的第3材料；上述第1層部，在上述旋轉中心軸心方向積疊於上述第2層部與上述第3層部之間。 For example, the bicycle sprocket according to item 8 of the scope of patent application, wherein the base body includes a third layer, and the third layer includes a third material having a smaller specific gravity than the first material; the first layer is at the center of rotation The axial direction is stacked between the second layer portion and the third layer portion. 如申請專利範圍第1至4項中任一項的自行車用鏈輪， 其中，上述鍍鎳層其維氏硬度(Vickers hardness)為500Hv以上。 Such as applying for a bicycle sprocket in any one of items 1 to 4 in the scope of patent application, Wherein, the above-mentioned nickel-plated layer has a Vickers hardness of 500 Hv or more. 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述基體包含鋁。 For example, the bicycle sprocket according to any one of items 1 to 4 in the scope of patent application, wherein the base body includes aluminum. 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述複數的齒部，包含在其與鏈條之間傳遞驅動力的驅動面，上述鍍鎳層形成於上述驅動面。 For example, the bicycle sprocket according to any one of items 1 to 4 in the scope of the patent application, wherein the plurality of teeth include a driving surface that transmits driving force between the tooth and the chain, and the nickel plating layer is formed on the driving surface . 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述鍍鎳層至少包含磷，上述鍍鎳層中的磷含有量為0.1質量%以上且10.0質量%以下。 The bicycle sprocket according to any one of items 1 to 4 in the scope of patent application, wherein the nickel-plated layer contains at least phosphorus, and the phosphorus content in the nickel-plated layer is 0.1% by mass or more and 10.0% by mass or less. 如申請專利範圍第16項的自行車用鏈輪，其中，上述鍍鎳層中的磷含有量為1.0質量%以上且5.0質量%以下。 For example, the bicycle sprocket according to the 16th patent application, wherein the phosphorus content in the nickel-plated layer is 1.0% by mass or more and 5.0% by mass or less. 如申請專利範圍第1項的自行車用鏈輪，其中，上述鍍鎳層中的硼含有量為0.1質量%以上且2.0質量%以下。 For example, the bicycle sprocket according to the first item of the scope of patent application, wherein the boron content in the nickel plating layer is 0.1% by mass or more and 2.0% by mass or less. 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述鍍鎳層包含無電解鍍鎳。 For example, the bicycle sprocket according to any one of items 1 to 4 in the scope of patent application, wherein the nickel plating layer includes electroless nickel plating. 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述鍍鎳層的厚度為1.0μm以上且100μm以下。 For example, the bicycle sprocket according to any one of items 1 to 4 in the scope of patent application, wherein the thickness of the nickel plating layer is 1.0 μm or more and 100 μm or less. 如申請專利範圍第20項的自行車用鏈輪，其中，上述鍍鎳層的厚度為5.0μm以上且40.0μm以下。 For example, the bicycle sprocket according to item 20 of the scope of patent application, wherein the thickness of the nickel-plated layer is 5.0 μm or more and 40.0 μm or less. 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述鏈輪主體包含：含有鋁的基體、及將上述基體的至少局部覆蓋的陽極氧化鋁覆膜。 The bicycle sprocket according to any one of items 1 to 4 in the scope of patent application, wherein the sprocket body includes a base body containing aluminum and an anodized aluminum film covering at least a part of the base body. 如申請專利範圍第1至4項中任一項的自行車用鏈輪，其中，上述自行車用鏈輪，是單片式的前鏈環。 For example, the bicycle sprocket according to any one of items 1 to 4 in the scope of patent application, wherein the bicycle sprocket is a single-piece front chain ring. 一種自行車用鏈輪組件，包含有：包含申請專利範圍第1至23項中任一項的自行車用鏈輪的第1鏈環、及包含較上述自行車用鏈輪更小直徑的自行車用鏈輪的第2鏈環。 A bicycle sprocket assembly, comprising: a first chain link including any one of the scope of patent application items 1 to 23, and a bicycle sprocket having a smaller diameter than the above-mentioned bicycle sprocket The second link. 如申請專利範圍第24項的自行車用鏈輪組件，其中，上述第2鏈環具備有複數的齒部，上述複數的齒部包含：在上述旋轉中心軸心方向具有第3寬度的第3齒部、與在上述旋轉中心軸心方向具有較上 述第3寬度更小的第4寬度的第4齒部。 For example, the bicycle sprocket assembly of claim 24, wherein the second chain ring is provided with a plurality of teeth, and the plurality of teeth includes: a third tooth having a third width in the direction of the rotation center axis Part, which has a higher The fourth tooth portion with the fourth width smaller than the third width. 如申請專利範圍第25項的自行車用鏈輪組件，其中，上述第3齒部及上述第4齒部包含：含有鋁的基體、及將上述基體的至少局部覆蓋的陽極氧化鋁覆膜。 For example, the bicycle sprocket assembly of claim 25, wherein the third tooth portion and the fourth tooth portion include a base containing aluminum, and an anodized aluminum film covering at least part of the base. 如申請專利範圍第25或26項的自行車用鏈輪組件，其中，上述第3齒部及上述第4齒部包含：含有鋁的基體、及將上述基體的至少局部覆蓋且包含磷及硼的至少其中一方的無電解鍍鎳。For example, the bicycle sprocket assembly of item 25 or 26 of the scope of patent application, wherein the third tooth portion and the fourth tooth portion include: a matrix containing aluminum, and a matrix that covers at least part of the matrix and contains phosphorus and boron At least one of them is electroless nickel plating.
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